Catalyst Systems and their use for Metathesis Reactions

ABSTRACT

A novel process for reducing the molecular weight of nitrile rubber in the presence of specific catalyst systems containing the metathesis catalyst and also a specific addition of fluorine-containing boron compounds is provided.

FIELD OF THE INVENTION

The present invention relates to catalyst systems, their use for thecatalysis of metathesis reactions and in particular a process forreducing the molecular weight of nitrile rubber by metathesis usingthese catalysts systems.

BACKGROUND OF THE INVENTION

Metathesis reactions are used widely in chemical syntheses, e.g. inring-closing metathesis (RCM), cross-metathesis (CM), ring-openingmetathesis (ROM), ring-opening metathesis polymerizations (ROMP), cyclicdiene metathesis polymerizations (ADMET), self-metathesis, reaction ofalkenes with alkynes (enyne reactions), polymerization of alkynes andolefinization of carbonyls (WO-A-97/06185 and Platinum Metals Rev.,2005, 49(3), 123-137). Metathesis reactions are employed, for example,for the synthesis of olefins, for the ring-opening polymerization ofnorbornene derivatives, for the depolymerization of unsaturated polymersand for the synthesis of telechelic polymers.

Metathesis catalysts are known, inter alia, from WO-A-96/04289 andWO-A-97/06185. They have the following basic structure:

where M is osmium or ruthenium, the radicals R are identical ordifferent organic radicals having a wide range of structures, X¹ and X²are anionic ligands and L is in each case an uncharged electron donor.The customary term “anionic ligands” is always used in the literatureconcerning such metathesis catalysts to describe ligands which, whenviewed as removed from the metal centre, are negatively charged whenthey have a closed electron shell.

Metathesis reactions have recently also become increasingly importantfor the degradation of nitrile rubbers.

The term nitrile rubber, also referred to as “NBR” for short, refers torubbers which are copolymers or terpolymeres of at least oneα,β-unsaturated nitrile, at least one conjugated diene and, ifappropriate, one or more further copolymerizable monomers.

Hydrated nitrile rubber, also referred to as “HNBR” for short, isproduced by hydration of nitrile rubber. Accordingly, the C═C doublebonds of the copolymerized diene units are completely or partly hydratedin HNBR. The degree of hydration of the copolymerized diene units isusually in the range from 50 to 100%. Hydrated nitrile rubber is aspeciality rubber which has very good heat resistance, excellentresistance to ozone and chemicals and also an excellent oil resistance.

The abovementioned physical and chemical properties of HNBR are combinedwith very good mechanical properties, in particular a high abrasionresistance. For this reason, HNBR has found wide use in a wide varietyof applications. HNBR is used, for example, for seals, hoses, belts anddamping elements in the automobile sector, also for stators, well sealsand valve seals in the field of oil production and also for numerousparts in the aircraft industry, the electrical industry, machineconstruction and shipbuilding.

Most commercially available HNBR grades usually have a Mooney viscosity(ML 1+4 at 100° C.) in the range from 55 to 120, which corresponds to anumber average molecular weight M_(n) (determination method: gelpermeation chromatography (GPC) against polystyrene standards) in therange from about 200 000 to 700 000. The polydispersity indices PDI(PDI=M_(W)/M_(n), where M_(w) is the weight average molecular weight andM_(n) is the number average molecular weight), which indicate the widthof the molecular weight distribution, measured here frequently have avalue of 3 or above. The residual double bond content is usually in therange from 0 to 18% (determined by NMR or IR spectroscopy). However, theterm “fully hydrated grades” is used in the technical field when theresidual double bond content is not more than about 0.9%.

The processability of HNBR grades having the abovementioned relativelyhigh Mooney viscosities is subject to limitations. For manyapplications, it is desirable to have HNBR grades which have a lowermolecular weight and thus a lower Mooney viscosity, since thissignificantly improves the processability.

Many attempts have been made in the past to shorten the chain length ofHNBR by degradation. For example, it is possible to reduce the molecularweight by thermomechanical treatment (mastication), e.g. on a roll millor also in a screw apparatus (EP A-0 419 952). However, thisthermomechanical degradation has the disadvantage that functional groupssuch as hydroxyl, keto, carboxylic acid and ester groups are built intothe molecule as a result of partial oxidation and, in addition, themicrostructure of the polymer is substantially altered.

The preparation of HNBR having low molar masses, corresponding to aMooney viscosity (ML 1+4 at 100° C.) in the range below 55 or a numberaverage molecular weight M_(n) of <200 000g/mol, has for a long time notbeen possible by means of established production processes since,firstly, a step increase in the Mooney viscosity occurs in the hydrationof NBR and, secondly, the molar mass of the NBR feedstock used for thehydration cannot be reduced at will since otherwise processing in theavailable industrial plants is no longer possible because of excessivehigh stickiness. The lowest Mooney viscosity of an NBR feedstock whichcan be processed without difficulties in an established industrial plantis about 30 Mooney units (ML 1+4 at 100° C.). The Mooney viscosity ofthe hydrated nitrile rubber obtained from such an NBR feedstock is inthe order of 55 Mooney units (ML 1+4 at 100° C.). The Mooney viscosityis determined in accordance with ASTM Standard D 1646.

In the more recent prior art, this problem is solved by reducing themolecular weight of the nitrile rubber by degradation to a Mooneyviscosity (ML 1+4 at 100° C.) of less than 30 Mooney units or a numberaverage molecular weight M_(n) of <70 000g/mol before hydration. Thedecrease in the molecular weight is achieved by metathesis in which lowmolecular weight 1-olefins are usually added. The metathesis of nitrilerubber is described, for example, in WO-A-02/100905, WO-A-02/100941 andWO-A-03/002613. The metathesis reaction is advantageously carried out inthe same solvent as the hydration reaction so that the degraded nitrilerubber does not have to be isolated from the solvent after thedegradation reaction is complete before it is subjected to thesubsequent hydration. The metathesis degradation reaction is catalysedusing metathesis catalysts which are tolerant to polar groups, inparticular nitrile groups.

WO-A-02/100905 and WO-A-02/100941 describe a process which comprises thedegradation of nitrile rubber starting polymers by olefin metathesis andsubsequent hydration to give HNBR having a low Mooney viscosity. Here, anitrile rubber is reacted in a first step in the presence of a coolefinand specific complex catalysts based on osmium, ruthenium, molybdenum ortungsten and hydrated in a second step. In this way, it is possible toobtain hydrated nitrile rubbers having a weight average molecular weight(M_(w)) in the range from 30 000 to 250 000, a Mooney viscosity (Mt 1+4at 100° C.) in the range from 3 to 50 and a polydispersity index PDI ofless than 2.5.

For the metathesis of nitrile rubber, it is possible to use, forexample, the catalyst bis(tricyclohexylphosphine)benzylidene rutheniumdichloride shown below.

After metathesis and hydration, the nitrile rubbers have a lowermolecular weight and a narrower molecular weight distribution than thehydrated nitrile rubbers which could hitherto be prepared according tothe prior art.

However, the amounts of Grubb (I) catalyst employed for carrying out themetathesis are large. In the experiments in WO-A-03/002613, they are,for example, 307 ppm and 61 ppm of Ru based on the nitrile rubber used.The reaction times necessary are also long and the molecular weightsafter degradation are always still relatively high (see Example 3 ofWO-A-03/002613, in which M_(w)=180 000g/mol and M_(n)=71 000g/mol).

US 2004/0127647 A1 describes blends based on low molecular weight HNBRrubbers having a bimodal or multimodal molecular weight distribution andvulcanizates of these rubbers. According to the examples, the metathesisis carried out using 0.5 phr of Grubbs I catalyst. This corresponds toan amount of 614 ppm of ruthenium based on the nitrile rubber used.

Furthermore, WO-A-00/71554 discloses a group of catalysts which arereferred to in the art as “Grubbs (II) catalysts”.

If such a “Grubbs (II) catalyst”, e.g. the catalyst1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidenylidene)(tricyclohexylphosphine)(phenylmethylene)rutheniumdichloride shown below, is used for the NBR metathesis(US-A-2004/0132891), this can be carried out successfully without use ofa coolefin.

After the subsequent hydration, which is preferably carried out in thesame solvent, the hydrated nitrile rubber has lower molecular weightsand a narrower molecular weight distribution (PDI) than when catalystsof the Grubbs (I) type are used. The metathetic degradation usingcatalysts of the Grubbs (II) type thus proceeds more efficiently inrespect of the molecular weight and the molecular weight distributionthan when using catalysts of the Grubbs (I) type. However, the amountsof ruthenium necessary for this efficient metathetic degradation arestill relatively high. In addition, long reaction times are stillrequired for carrying out the metathesis using the Grubbs (II) catalyst.

In all the abovementioned processes for the metathetic degradation ofnitrile rubber, relatively large amounts of catalyst have to be used andlong reaction times are required in order to prepare the desired lowmolecular weight nitrile rubbers by means of metathesis.

In the other types of metathesis reactions, too, the activity of thecatalysts used is of critical importance.

In J. Am.Chem. Soc. 1997, 119, 3887-3897, it is stated that in thering-closing metathesis of diethyl diallylmalonate shown below,

the activity of the catalysts of the Grubbs (I) type can be increased byadditions of CuCl and CuCl₂. This activity increase is explained by ashift in the dissociation equilibrium as a result of which a phosphaneligand which has been released reacts with copper ions to formcopper-phosphane complexes.

However, this activity increase brought about by copper salts in thering-closing metathesis mentioned cannot be applied at will to othertypes of metathesis reactions. Our own studies have shown that althoughthe addition of copper salts leads to an initial acceleration of themetathetic degradation of nitrile rubbers, a significant worsening ofthe efficiency of the metathesis is then unexpectedly observed: themolecular weights of the degraded nitrile rubbers which are ultimatelyachieved are substantially higher than when the metathesis reaction iscarried out in the presence of the same catalyst but in the absence ofthe copper salts.

EP-A-1 825 913 describes new catalyst systems for metathesis, in whichnot only the actual metathesis catalyst but also one or more salts areused. This combination of one or more salts with the metathesis catalystleads to an increase in the activity of the catalyst, a synergisticeffect. The anions and cations of these salts can have a large number ofmeanings which can be selected from various lists. In the examples ofEP-A-1 825 913, the use of lithium bromide is found to be particularlyadvantageous both for the metathetic degradation of rubbers such asnitrile rubbers and also for the ring-closing metathesis of diethyldiallylmalonate. Catalysts mentioned are, in particular, ones whichcoordinate via an oxygen-, nitrogen- or sulphur-containing substituentto the metal centre of a ruthenium- or osmium-carbene. Use is made of,for example, the Grubbs (H) catalyst, the Hoveyda catalyst, theBuchmeiser-Nuyken catalyst and the Grela catalyst.

An as yet unpublished German patent application describes specificcatalyst systems for metathesis, which comprise not only the actualmetathesis catalyst but also alkaline earth metal chlorides, preferablymagnesium or calcium chloride, as added salts.

EP-A-1 894 946 describes an increase in activity of metathesis catalystsas a result of specific phosphane additions.

The increase in activity of metathesis catalysts brought about by saltshas likewise been studied in Inorganica Chimica Acta 359 (2006)2910-2917. The influences of tin chloride, tin bromide, tin iodide,iron(II) chloride, iron(II) bromide, iron(III) chloride, cerium(III)chloride*7H₂O, ytterbium(III) chloride, antimony trichloride, galliumdichloride and aluminium trichloride on the self-metathesis of 1-octeneto form 7-tetradecene and ethylene were examined. When using the Grubbs(I) catalyst, a significant improvement in the conversion to7-tetradecene was observed when tin chloride or tin bromide was added(Table 1; catalyst 1). Without addition of salt, a conversion of 25.8%was achieved; when 5 nCl₂*2H₂O was added, the conversion rose to 68.5%and when tin bromide was added it rose to 71.9%. Addition of tin iodideresulted in a significant decrease in the conversion from 25.8% to 4.1%.In combination with the Grubbs (II) catalyst (Table 1; catalyst 2), onthe other hand, all three tin salts led to only slight improvements inyield from 76.3% (reference experiment without addition) to 78.1%(SnCl₂), to 79.5% (SnBr₂) and 77.6% (SnI₂). When “phobcat”[Ru(phobCy)₂Cl₂(-50 ChPh)] is used (Table 1; catalyst 3), the conversionis decreased from 87.9% to 80.8% by addition of SnCl₂, to 81.6% by SnBr₂and to 73.9% by SnI₂. When iron(II) salts are used in combination withthe Grubbs (I) catalyst (Table 3; catalyst 1), the increase inconversion when using iron(II) bromide is higher than when usingiron(II) chloride. It may be remarked that, regardless of the type ofcatalyst used, the conversion when bromides are used is always higherthan when the corresponding chlorides are used.

However, the use of tin or iron(II) bromide described in InorganicaChimica Acta 359 (2006) 2910-2917 is not an optimal solution for thepreparation of nitrile rubbers because of the corrosive nature of thebromides.

In the preparation of hydrated nitrile rubbers, the solvent is usuallyremoved by steam distillation after the hydration. If tin salts are usedas part of the catalyst system, amounts of these tin salts get into thewastewater which therefore has to be subjected to costly purification.For this reason, the use of tin salts for increasing the activity ofcatalysts in the preparation of nitrile rubbers is not advisable from aneconomic point of view.

The use of iron salts is restricted by the fact that they reduce thecapacity of some ion-exchange resins which are usually employed forrecovering the noble metal compounds used in the hydration. Thislikewise adversely affects the economics of the overall process.

ChemBioChem 2003, 4, 1229-1231 describes the synthesis of polymers by aring-opening metathesis polymerization (ROMP) of norbornyl oligopeptidesin the presence of a ruthenium-carbene complex Cl₂(PCy₃)₂Ru═CHphenyl,with lithium chloride being added. The addition of lithium chloride iscarried out with the declared objective of avoiding aggregation andincreasing the solubility of the growing polymer chains. Nothing is saidabout an activity-increasing effect of the addition of the salt on thecatalyst.

A method of carrying out a ring-opening polymerization ofoligopeptide-substituted norbornenes is also known from J. Org. Chem.2003, 68, 2020-2023, in which lithium chloride is used. Here too, theinfluence of lithium chloride as solubility-increasing additive for thepeptides in nonpolar organic solvents is emphasized. For this reason, anincrease in the degree of polymerization “DP” can be achieved by theaddition of lithium chloride.

In J. Am. Chem. Soc. 1997, 119, 3887-3897 it is stated that when LiBr orNaI is added to a metathesis catalyst containing NHC ligands, e.g. theGrubbs (II) catalyst, the chloride ligands are replaced by bromide oriodide. Furthermore, it is shown that the catalyst activity depends onthe type of halide ligands and increases in the following order:I<Br<Cl.

In J. Am. Chem. Soc. 1997, 119, 9130-9136 it is stated that the activityof the Grubbs (I) catalyst in the ring-closing metathesis of 1,co-dienescan be increased by addition of tetraisopropoxytitanate and animprovement in yield can be achieved thereby. In the cyclization of the9-decenoic ester of 4-pentenoate, a higher yield of the macrolide isachieved when tetraisopropanoxytitanate is added than when LiBr isadded. There is no indication of the extent to which this effect canalso be applied to other types of metathesis reactions or othermetathesis catalysts.

In Org. Biomol. Chem. 2005, 3, 4139-4142 the cross-metathesis (CM) ofacrylonitrile with itself and with other functional olefins when using[1,3-bis(2,6-dimethylphenyl)-4,5-dihydroimidazol-2-ylidene](C₅H₅N)₂(Cl)₂Ru═CHPhis examined. The yield of the respective product is improved by additionof tetraisopropoxytitanate. This publication gives the impression thatthe activity-increasing effect of tetraisopropoxytitanate occurs onlywhen using a specific catalyst having pyridine ligands. There is nosuggestion of an influence of tetraisopropoxytitanate when pyridine-freecatalysts are used or in other types of metathesis reactions.

It is known from Synlett 2005, No. 4, 670-672 that the addition oftetraisopropoxytitanate in the cross-metathesis of allyl carbamate withmethyl acrylate has an adverse effect on the product yield when theHoveyda catalyst is used as catalyst. Thus, the product yield is reducedfrom 28% to 0% by addition of tetraisopropoxytitanate. Addition ofdimethylaluminium chloride, too, reduces the yield from 28% to 20%.

In Synlett 2005, No. 4, 670-672 it is also stated that the product yieldin the cross-metathesis of low molecular weight olefins is improved whenspecific boric acid derivatives are used. Use is made ofchlorochatecholborane (ArO₂BC1), dichlorophenylborane (PhBCl₂) andchlorodicyclohexylborane (Cy₂BCl). Depending on the boric acidderivative, the yield is improved to very different extents. To obtainappropriate improvements in yield, addition of 10-20 mol % of the boricacid derivative based on 1 equivalent of an olefin is required.

In Synthesis 2000, No. 12, 1766-1773 it is stated that the yields in thering-closing metathesis of diethyl diallylmalonate when using the GrubbsI catalyst are not adversely affected by additions of boron trichlorideand aluminium trichloride (Table 2). In a tandem enynemethathesis/Diels-Alder reaction ofN-allyl-N-3-phenylprop-2-ynyl-p-toluenesulphenamide to form4-acyl-7-phenyl-hexahydroisoindole viaN-tosyl-1-(1-phenylvinyl)-2,4-dihydro-2H-pyrrole (as intermediateproduct of the enyne methathesis), too, the yield is not influenced bywhether BCl₃ is added right at the beginning together with the Grubbs(I) catalyst in a one-pot reaction or whether it is, in a sequentialprocedure, added only in the second step of the Diels-Alder reaction.These experiments show that the activity of the Grubbs (I) catalyst isnot reduced by addition of boron trichloride or aluminium trichloride.However, there is no evidence that addition of boron trichloride oraluminium trichloride improves the catalyst activity.

Since the metathesis reaction is enjoying increasing popularity both inthe field of low molecular weight chemistry and for polymers such asnitrile rubbers, there is, despite the existing prior art, a continuingneed for improved catalyst systems for metathesis reactions and inparticular the reduction of the molecular weight of nitrile rubber bymetathesis. This applies all the more in view of the fact that, on thebasis of the available prior art, results of one metathesis reactioncannot readily be applied to another.

In the light of this background, it is an object of the presentinvention to provide novel catalyst systems which can be useduniversally in various types of metathesis reactions, lead to activityincreases for a wide variety of metathesis catalysts used as a basis andthus allow a reduction in the amount of catalyst and thus, inparticular, the amounts of noble metal present therein. For themetathetic degradation of nitrile rubber in particular, possible ways ofincreasing the activity of the catalyst used without gelling of thenitrile rubber should be found.

SUMMARY OF THE INVENTION

It has surprisingly been found that the activity of metathesis catalystscan be increased significantly when they are used in combination withfluorine-containing boron compounds. In particular, it has been foundthat the reduction of the molecular weight of nitrile rubber bymetathesis can be significantly improved when the metathesis catalyst isused as a system in combination with fluorine-containing boroncompounds. This combination increases the reaction rate of metathesisreactions and, particularly in the metathesis of NBR, significantlynarrower molecular weight distributions and lower molecular weights canbe obtained without gelling occurring. At the same time, the amount ofmetathesis catalyst can be reduced by the addition of thefluorine-containing boron compounds.

DETAILED DESCRIPTION OF THE INVENTION

The invention accordingly provides a process for the metatheticdegradation of nitrile rubbers, in which the nitrile rubber is subjectedto a metathesis reaction in the presence of a catalyst system, whereinthe catalyst system contains a metathesis catalyst which is a complexcatalyst based on a metal of transition group 6 or 8 of the PeriodicTable and has at least one ligand bound in a carbene-like fashion to themetal and also at least one compound of the general formula (Z)

BF_(m)X_(n)*D_(v)  (Z)

where

-   m is 1, 2 or 3,-   n is 0, 1 or 2 and at the same time-   m+n=3 and-   v is 1, 2, 3, 4 or 5,-   X is chlorine, bromine, iodine, an —OR or —NR₂ group, where the    radicals R are each, independently of one another, a linear,    branched, aliphatic, cyclic, heterocyclic or aromatic radical which    has 1-33 carbon atoms and may optionally have from 1 to 15 further    heteroatoms, and-   D is a compound having at least one free electron pair, where D    contains at least one heteroatom which is preferably selected from    the group consisting of oxygen, sulphur, nitrogen, phosphorus,    arsenic and antimony.

In a preferred embodiment of the invention, compounds of the generalformula (Z) in which X is chlorine, bromine or an —OR or —NR₂ group,where the radicals R are each, independently of one another,straight-chain or branched C₁-C_(m)-alkyl, preferably C₁-C₂₀-alkyl,particularly preferably C₁-C₁₂-alkyl, C₃-C₂₀-cycloalkyl, preferablyC₃-C₁₀-cycloalkyl, particularly preferably C₅-C₈-cycloalkyl,C₂-C₂₀-alkenyl, preferably C₂-C₁₈-alkenyl, C₂-C₂₀-alkynyl, preferablyC₂-C₁₈-alkynyl, C₆-C₂₄-aryl, preferably C₆-C₁₄-aryl, C₄-C₂₃-heteroaryl,where these heteroaryl radicals have at least one heteroatom, preferablynitrogen or oxygen, or are in each case a radical of the general formula(—CHZ¹-CHZ¹-A²-)_(p)—CH₂—CH₃, where p is an integer from 1 to 10, theradicals Z¹ are identical or different and are each hydrogen or methyl,with the radicals Z¹ located on adjacent carbon atoms preferably beingdifferent, and A² is oxygen, sulphur or —NH, are used in the catalystsystem.

In a particularly preferred embodiment of the invention, compounds ofthe general formula (Z) in which the radicals R in the radicals OR andNR₂ are each methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl,tert-butyl, n-pentyl, i-pentyl, tert-pentyl, hexyl, decyl, dodecyl,oleyl, phenyl or sterically hindered phenyl are used in the catalystsystem.

In the general formula (Z), the BF_(m)X_(n) moiety is preferably BF₃,BF₂Cl, BFCl₂ BF₂Br, BFBr₂, BF₂(OC₂H₅), BF(OC₂H₅)₂, BF₂(CH₃) andBF(CH₃)₂. BF_(m)X_(n) is particularly preferably BF₃.

In the compounds of the general formula (Z), D can have the followingmeanings of the general formulae (2) to (16)

OR₂  (2)

ROH  (3)

R—COOH  (4)

SR₂  (5)

O═SR₂  (6)

O₂SR₂  (7)

NHR₂, NH₂R, NR₃,  (8a, 8b, 8c)

YR₃, R₂Y—YR₂  (9a, 9b)

O═YR₃  (10)

O═Y(OR)₂  (11)

O═Y(OR)₃  (12)

O═CR₂  (13)

S═YR₃  (14)

H₂SO₄  (15)

RSO₃H  (16)

where Y is phosphorus, arsenic or antimony and the radicals R areidentical or different and are each hydrogen or a linear, branched,aliphatic, cyclic, heterocyclic or aromatic radical which has 1-33carbon atoms and may be bridged and can optionally have from 1 to 15further heteroatoms, preferably nitrogen or oxygen, or can optionally besubstituted. Preference is given to the radicals R each being,independently of one another, hydrogen, straight-chain or branchedC₁-C₃₀-alkyl, particularly preferably straight-chain or branchedC₁-C₁₂-alkyl, C₃-C₂₀-cycloalkyl, particularly preferablyC₅-C₈-cycloalkyl, straight-chain or branched C₂-C₂₀-alkenyl,particularly preferably straight-chain or branched C₂-C₁₄-alkenyl,straight-chain or branched C₂-C₂₀-alkynyl, particularly preferablystraight-chain or branched C₂-C₁₄-alkynyl, C₆-C₂₄-aryl, particularlypreferably C₆-C₁₄-aryl, where all the abovementioned radicals may eachoptionally be substituted by one or more alkyl, halogen, preferablyfluorine or chlorine, alkoxy, aryl or heteroaryl radicals. If tworadicals R are present in one of the formulae (2)-(16), these can alsobe bridged with inclusion of the common atom or atoms to which they arebound to form a cyclic group which can be aliphatic or aromatic innature, may optionally be substituted and can additionally contain oneor more heteroatoms, preferably oxygen or nitrogen.

Examples of compounds D of the general formula (2) are: water, dimethylether, diethyl ether, di-n-propyl ether, di-i-propyl ether, di-n-butylether, di-i-butyl ether, di-t-butyl ether, methyl t-butyl ether,dimethoxyethane, di-n-butoxyethane, diphenyl ether, methylphenyl ether,ethylphenyl ether, tetrahydrofuran, tetrahydropyran. Preference is givento water, diethyl ether, tetrahydrofuran and tetrahydropyran.

Examples of compounds D of the general formula (3) are: methanol,ethanol, n-propanol, i-propanol, n-butanol, t-butanol, phenol, catechol,anisole and salicylic acid.

Examples of compounds D of the general formula (4) are: formic acid,acetic acid, propionic acid, citric acid, trichloroacetic acid,trifluoroacetic acid and benzoic acid.

Examples of compounds D of the general formula (5) are: hydrogensulphide, methyl mercaptan, n-hexyl mercaptan, t-butyl mercaptan,t-nonyl mercaptan, n-dodecyl mercaptan and t-dodecyl mercaptan, dimethylsulphide, diethyl sulphide, diisopropyl sulphide, tetrahydrothiopheneand diphenyl sulphide.

Examples of compounds D of the general formula (6) are dimethylsulphoxide, diethyl sulphoxide, diisopropyl sulphoxide, butyl methylsulphoxide and tetrahydrothiophene 1-oxide.

Examples of compounds D of the general formula (7) are dimethylsulphone, diethyl sulphone, diisopropyl sulphone, butyl methyl sulphoneand Sulpholane (tetrahydrothiophene 1,1-dioxide).

Examples of compounds D of the general formulae (8a, 8b and 8c) are:trimethylamine, triethylamine, triethanolamine, aniline, methylaniline,dimethylaniline, pyridine, pyrimidine, pyrrole, pyrrolidine,tetramethylethylenediamine, tetraethylethylenediamine, ammonia,methylamine, ethylamine, propylamine, diethylamine and dimethylamine.

Examples of compounds D of the general formula (9a) are: phosphine,trimethylphosphine, triethylphosphine, triisopropylphosphine,tricyclohexylphosphine, triphenylphosphine andtris(sulphonophenyl)phosphane and salts thereof.

An example of a compound D of the general formula (9b) istetraphenyldiphosphane.

Particular preference is given to using water, diethyl ether,ethylamine, THF, n-propanol, formic acid, acetic acid, trifluoroaceticacid, trichloroacetic acid, sulphuric acid, phosphoric acid,trifluoromethanesulphonic acid and toluenesulphonic acid as compounds D.

For the purposes of the present patent application and invention, alldefinitions mentioned above and below, in general terms or in preferredranges, of radicals, parameters or explanations can be combined with oneanother, i.e. also between the respective ranges and preferred ranges,in any desired way.

The term “substituted” used in the present patent application inrelation to the various types of metathesis catalysts or compounds ofthe general formula (Z) means that a hydrogen atom on the indicatedradical or atom has been replaced by one of the groups indicated in eachcase, with the proviso that the valency of the indicated atom is notexceeded and the substitution leads to a stable compound.

The metathesis catalysts to be used in the process of the invention arecomplex catalysts based on a metal of transition group 6 or 8 of thePeriodic Table. These complex catalysts have the common structuralfeature that they have at least one ligand which is bound to the metalin a carbene-like fashion. In a preferred embodiment, the complexcatalyst has two carbene ligands, i.e. two ligands which are bound in acarbene-like fashion to the central metal of the complex. As metals oftransition groups 6 and 8 of the Periodic Table, preference is given tomolybdenum, tungsten, osmium and ruthenium.

Suitable catalyst systems are, for example, systems which comprise atleast one compound of the general formula (Z) and also a catalyst of thegeneral formula A),

where

-   M is osmium or ruthenium,-   X¹ and X² are identical or different and are two ligands, preferably    anionic ligands,-   L represents identical or different ligands, preferably uncharged    electron donors,-   the radicals R are identical or different and are each hydrogen,    alkyl, preferably C₁-C₃₀-alkyl, cycloalkyl, preferably    C₃-C₂₀-cycloalkyl, alkenyl, preferably C₂-C₂₀-alkenyl, alkynyl,    preferably C₂-C₂₀-alkynyl, aryl, preferably C₆-C₂₄-aryl,    carboxylate, preferably C₁-C₂₀-carboxylate, alkoxy, preferably    C₁-C₂₀-alkoxy, alkenyloxy, preferably C₂-C₂₀-alkenyloxy, alkynyloxy,    preferably C₂-C₂₀-alkynyloxy, aryloxy, preferably C₆-C₂₄-aryloxy,    alkoxycarbonyl, preferably C₂-C₂₀-alkoxycarbonyl, alkylamino,    preferably C₁-C₃₀-alkylamino, alkylthio, preferably    C₁-C₃₀-alkylthio, arylthio, preferably C₆-C₂₄-arylthio,    alkylsulphonyl, preferably C₁-C₂₀-alkylsulphonyl, or alkylsulphinyl,    preferably C₁-C₂₀-alkylsulphinyl, where these radicals can all    optionally be substituted by one or more alkyl, halogen, alkoxy,    aryl or heteroaryl radicals or alternatively the two radicals R are    bridged with inclusion of the common C atom to which they are bound    to form a cyclic group which can be aliphatic or aromatic in nature,    may optionally be substituted and can contain one or more    heteroatoms.

In a preferred embodiment, these catalyst systems comprise a catalyst ofthe general formula (A) together with a compound of the general formula(Z) in which the BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂,BF₂(OC₂H₅), BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from thegroup consisting of water, diethyl ether, ethylamine, THF, n-propanol,formic acid, acetic acid, trifluoroacetic acid, trichloroacetic acid,sulphuric acid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

In particularly preferred catalysts of the general formula (A), oneradical R is hydrogen and the other radical R is C₁-C₂₀-alkyl,C₃-C₁₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy,C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl, C₁-C₃₀-alkylamino,C₁-C₃₀-alkylthio, C₆-C₂₄-arylthio, C₁-C₂₀-alkylsulphonyl orC₁-C₂₀-alkylsulphinyl, where these radicals can all be substituted byone or more alkyl, halogen, alkoxy, aryl or heteroaryl radicals.

In the catalysts of the general formula (A), X¹ and X² are identical ordifferent and are two ligands, preferably anionic ligands.

X¹ and X² can be, for example, hydrogen, halogen, pseudohalogen,straight-chain or branched C₁-C₃₀ alkyl, C₆-C₂₄-aryl, C₁-C₂₀-alkoxy,C₆-C₂₄-aryloxy, C₃-C₂₀-alkyldiketonate, C₆-C₂₄-aryldiketonate,C₁-C₂₀-carboxylate, C₁-C₂₀-alkylsulphonate, C₆-C₂₄-arylsulphonate,C₁-C₂₀-alkylthiol, C₆-C₂₄-arylthiol, C₁-C₂₀-alkylsulphonyl orC₁-C₂₀-alkylsulphinyl radicals.

The abovementioned radicals X¹ and X² can also be substituted by one ormore further radicals, for example by halogen, preferably fluorine,C₁-C₁₀-alkyl, C₁-C₁₀-alkoxy or C₆-C₂₄-aryl, where these radicals too mayoptionally be substituted by one or more substituents selected from thegroup consisting of halogen, preferably fluorine, C₁-C₅-alkyl,C₁-C₅-alkoxy and phenyl.

In a preferred embodiment, X¹ and X² are identical or different and areeach halogen, in particular fluorine, chlorine, bromine or iodine,benzoate, C₁-C₅-carboxylate, C₁-C₅-alkyl, phenoxy, C₁-C₅-alkoxy,C₁-C₅-alkylthiol, C₆-C₂₄-arylthiol, C₆-C₂₄-aryl orC₁-C₅-alkylsulphonate.

In a particularly preferred embodiment, X¹ and X² are identical and areeach halogen, in particular chlorine, CF₃COO, CH₃COO, CFH₂COO, (CH₃)₃CO₃(CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO (phenoxy), MeO (methoxy), EtO(ethoxy), tosylate (p-CH₃—C₆H₄—SO₃), mesylate (2,4,6-trimethylphenyl) orCF₃SO₃ (trifluoromethanesulphonate).

In the general formula (A), L represents identical or different ligandsand preferably uncharged electron donors.

The two ligands L can, for example, each be, independently of oneanother, a phosphine, sulphonated phosphine, phosphate, phosphinite,phosphonite, arsine, stibine, ether, amine, amide, sulphoxide, carboxyl,nitrosyl, pyridine, thioether or imidazolidine (“Im”) ligand.

Preference is given to the two ligands L each being, independently ofone another, a C₆-C₂₄-arylphosphine, C₁-C₁₀-alkylphosphine orC₃-C₂₀-cycloalkylphosphine ligand, a sulphonated C₆-C₂₄-arylphosphine orsulphonated C₁-C₁₀-alkylphosphine ligand, a C₆-C₂₄-arylphosphinite orC₁-C₁₀-alkylphosphinite ligand, a C₆-C₂₄-arylphosphonite orC₁-C₁₀-alkylphosphonite ligand, a C₆-C₂₄-aryl phosphite or C₁-C₁₀-alkylphosphite ligand, a C₆-C₂₄-arylarsine or C₁-C₁₀-alkylarsine ligand, aC₆-C₂₄-arylamine or C₁-C₁₀-alkylamine ligand, a pyridine ligand, aC₆-C₂₄-aryl sulphoxide or C₁-C₁₀-alkyl sulphoxide ligand, a C₆-C₂₄-arylether or C₁-C₁₀-alkyl ether ligand or a C₆-C₂₄-arylamide orC₁-C₁₀-alkylamide ligand, which can all be substituted by a phenyl groupwhich may in turn optionally be substituted by a halogen, C₁-C₅-alkyl orC₁-C₅-alkoxy radical.

The term “phosphine” includes, for example, PPh₃, P(p-tolyl)₃,P(o-tolyl)₃, Pphenyl(CH₃)₂, P(CF₃)₃, P(p-FC₆R₄)₃, P(p-CF₃C₆H₄)₃,P(C₆H₄—SO₃Na)₃, P(CH₂C₆H₄—SO₃Na)₃, P(isopropyl)₃, P(CHCH₃(CH₂CH₃))₃,P(cyclopentyl)₃, P(cyclohexyl)₃, P(neopentyl)₃ and P(neophenyl)₃.

The term “phosphinite” includes, for example, phenyldiphenylphosphinite, cyclohexyl dicyclohexylphosphinite, isopropyldiisopropylphosphinite and methyl diphenylphosphinite.

The term “phosphite” includes, for example, triphenyl phosphite,tricyclohexyl phosphite, tri-tert-butyl phosphite, triisopropylphosphite and methyl diphenyl phosphite.

The term “stibine” includes, for example, triphenylstibine,tricyclohexylstibine and trimethylstiben.

The term “sulphonate” includes, for example, trifluoromethanesulphonate,tosylate and mesylate.

The term “sulphoxide” includes, for example, (CH₃)₂S(═O) and (C₆H₅)₂SO.

The term “thioether” includes, for example, CH₃SCH₃, C₆H₅SCH₃,CH₃OCH₂CH₂SCH₃ and tetrahydrothiophene.

For the purposes of the present patent application, the term “pyridine”serves as collective term for all nitrogen-containing ligands as arementioned, for example, in WO-A-03/011455. Examples are: pyridine,picolines (α-, β-, and γ-picoline), lutidines (2,3-, 2,4-, 2,5-, 2,6-,3,4- and 3,5-lutidine), collidine (2,4,6-trimethylpyridine),trifluoromethylpyridine, phenylpyridine, 4-(dimethylamino)pyridine,chloropyridines, bromopyridines, nitropyridines, quinoline, pyrimidine,pyrrole, imidazole and phenylimidazole.

If one or both of the ligands L is an imidazolidine radical (Im), thisusually has a structure of the general formula (IIa) or (IIb),

where

-   R⁸, R⁹, R¹⁰, R¹¹ are identical or different and are each hydrogen,    straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,    C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate,    C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₇₀-alkynyloxy, C₆-C₂₀-aryloxy,    C₂-C₇₀-alkoxycarbonyl, C₁-C₇₀-alkylthio, C₆-C₂₀-arylthio,    C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphonate, C₆-C₂₀-arylsulphonate    or C₁-C₂₀-alkylsulphinyl.

One or more of the radicals R⁸, R⁹, R¹⁰, R¹¹ can optionally besubstituted, independently of one another, by one or more substituents,preferably straight-chain or branched C₁-C₁₀-alkyl, C₃-C₈-cycloalkyl,C₁-C₁₀-alkoxy or C₆-C₂₄-aryl, where these abovementioned substituentsmay in turn be substituted by one or more radicals, preferably radicalsselected from the group consisting of halogen, in particular chlorine orbromine, C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

Purely for the purposes of clarification, it may be added that thestructures of the imidazolidine radical shown in the general formulae(IIa) and (IIb) in the present patent application are equivalent to thestructures (IIa′) and (IIb′) for this imidazolidine radical (Im) whichare frequently also to be found in the literature and emphasize thecarbene character of the imidazolidine radical. This applies analogouslyto the associated preferred structures (IIIa)-(IIIf) shown below.

In a preferred embodiment of the catalysts of the general formula (A),R⁸ and R⁹ are each, independently of one another, hydrogen, C₆-C₂₄-aryl,particularly preferably phenyl, straight-chain or branched C₁-C₁₀-alkyl,particularly preferably propyl or butyl, or together with the carbonatoms to which they are bound form a cycloalkyl or aryl radical, whereall the abovementioned radicals may in turn optionally be substituted byone or more further radicals selected from the group consisting ofstraight-chain or branched C₁-C₁₀-alkyl, C₁-C₁₀-alkoxy, C₆-C₂₄-aryl anda functional group selected from the group consisting of hydroxy, thiol,thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro,carboxylic acid, disulphide, carbonate, isocyanate, carbodiimide,carboalkoxy, carbamate and halogen.

In a preferred embodiment of the catalysts of the general formula (A),the radicals R¹⁰ and R¹¹ are identical or different and are eachstraight-chain or branched C₁-C₁₀-alkyl, particularly preferablyi-propyl or neopentyl, C₃-C₁₀-cycloalkyl, particularly adamantyl,C₆-C₂₄-aryl, particularly preferably phenyl, C₁-C₁₀-alkylsulphonate,particularly preferably methanesulphonate, C₆-C₁₀-arylsulphonate,particularly preferably p-toluenesulphonate.

The abovementioned radicals as meanings of R¹⁰ and R¹¹ may optionally besubstituted by one or ore further radicals selected from the groupconsisting of straight-chain or branched C₁-C₅-alkyl, in particularmethyl, C₁-C₅-alkoxy, aryl and a functional group selected from thegroup consisting of hydroxy, thiol, thioether, ketone, aldehyde, ester,ether, amine, imine, amide, nitro, carboxylic acid, disulphide,carbonate, isocyanate, carbodiimide, carboxalkoxy, carbamate andhalogen.

In particular, the radicals R¹⁰ and R¹¹ can be identical or differentand are each i-propyl, neopentyl, adamantyl, mesityl or2,6-diisopropylphenyl.

Particularly preferred imidazolidine radicals (Im) have the followingstructures (IIIa) to (IIIf), where Ph is in each case a phenyl radical,Bu is a butyl radical and Mes is in each case a 2,4,6-trimethylphenylradical or Mes is alternatively in all cases 2,6-diisopropylphenyl.

Various representatives of the catalysts of the formula (A) are known inprinciple, e.g. from WO-A-96/04289 and WO-A-97/06185.

As an alternative to the preferred Im radicals, one or both of theligands L in the general formula (A) are preferably also identical ordifferent trialkylphosphine ligands in which at least one of the alkylgroups is a secondary alkyl group or a cycloalkyl group, preferablyisopropyl, isobutyl, sec-butyl, neopentyl, cyclopentyl or cyclohexyl.

Particular preference is given to one or both of the ligands L in thegeneral formula (A) being a trialkylphosphine ligand in which at leastone of the alkyl groups is a secondary alkyl group or a cycloalkylgroup, preferably isopropyl, isobutyl, sec-butyl, neopentyl, cyclopentylor cyclohexyl.

Particular preference is given to catalyst systems which comprise atleast one compound of the general formula (Z) together with one of thefollowing two catalysts which come under the general formula (A) andhave the structures (IV) (Grubbs (I) catalyst) and (V) (Grubbs (II)catalyst), where Cy is cyclohexyl and Mes is meistyl.

In a further embodiment, a catalyst system comprising at least onecompound of the general formula (Z) together with a catalyst of thegeneral formula (A1),

where

-   X¹, X² and L can have the same general, preferred and particularly    preferred meanings as in the general formula (A),-   n is 0, 1 or 2,-   m is 0, 1, 2, 3 or 4 and-   the radicals R′ are identical or different and are each an alkyl,    cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy,    aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio,    alkylsulphonyl or alkylsulphinyl radical, which may all be    substituted by one or more alkyl, halogen, alkoxy, aryl or    heteroaryl radicals,    is used in the process of the invention.

As preferred catalyst which comes under the general formula (A1), it ispossible to use, for example, the catalyst of the formula (VI) below,where Mes is in each case 2,4,6-trimethylphenyl and Ph is phenyl.

This catalyst which is also referred to in the literature as “Nolancatalyst” is known, for example, from WO-A-2004/112951.

The particularly preferred catalyst systems comprise the catalysts ofthe formula (IV), (V) or (VI) together with a compound of the generalformula (Z) in which the BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂ BF,Br,BFBr₂, BF₂(OC₂H₅), BR(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected fromthe group consisting of water, diethyl ether, ethylamine, THF,n-propanol, formic acid, acetic acid, trifluoroacetic acid,trichloroacetic acid, sulphuric acid, phosphoric acid,trifluoromethanesulphonic acid and toluenesulphonic acid and v=1, 2, 3,4 or 5, particularly preferably 1, 2 or 3.

Further suitable catalyst systems are systems which comprise at leastone compound of the general formula (Z) together with a catalyst of thegeneral formula (B),

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different ligands, preferably anionic    ligands,-   Y is oxygen (O), sulphur (S), an N—R¹ radical or a P—R¹ radical,    where R¹ has the meanings mentioned below,-   R¹ is an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy,    alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino,    alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl radical, which    may all optionally be substituted by one or more alkyl, halogen,    alkoxy, aryl or heteroaryl radicals,-   R², R³, R⁴ and R⁵ are identical or different and are each hydrogen    or an organic or inorganic radical,-   R⁶ is hydrogen or an alkyl, alkenyl, alkynyl or aryl radical and-   L is a ligand which has the same meanings as mentioned for the    formula (A).

These catalyst systems preferably comprise the catalyst of the generalformula (B) together with a compound of the general formula (Z) in whichthe BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂, BF₂(OEt),BF(OEt)₂, BF₂(Me) or BF(Me)₂, D is selected from the group consisting ofwater, diethyl ether, ethylamine, THF, n-propanol, formic acid, aceticacid, trifluoroacetic acid, trichloroacetic acid, sulphuric acid,phosphoric acid, trifluoromethanesulphonic acid and toluenesulphonicacid and v=1, 2, 3, 4 or 5, particularly preferably 1, 2 or 3.

The catalysts of the general formula (B) are known in principle.Representatives of this class of compounds are the catalysts describedby Hoveyda et al. in US 2002/0107138 A1 and Angew. Chem. Int. Ed. 2003,42, 4592 and the catalysts which are described by Grela inWO-A-2004/035596, Eur. J. Org. Chem. 2003, 963-966 and Angew. Chem. Int.Ed. 2002, 41, 4038 and in J. Org. Chem. 2004, 69, 6894-96 and Chem. Eur.J. 2004, 10, 777-784. The catalysts are commercially available or can beprepared as described in the literature references cited.

In the catalysts of the general formula (B), L is a ligand which usuallyhas an electron donor function and can have the same general, preferredand particularly preferred meanings as L in the general formula (A).

In addition, L in the general formula (B) is preferably a P(R⁷)₃radical, where the radicals R⁷ are each, independently of one another,C₁-C₆-alkyl, C₃-C₈-cycloalkyl or aryl, or else a substituted orunsubstituted imidazolidine radical (“Im”).

C₁-C₆-alkyl is, for example, methyl, ethyl, n-propyl, isopropyl,n-butyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl,3-methylbutyl, neopentyl, 1-ethylpropyl or n-hexyl.

C₃-C₈-cycloalkyl encompasses cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl and cyclooctyl.

Aryl is an aromatic radical having from 6 to 24 skeletal carbon atoms.As preferred monocyclic, bicyclic or tricyclic carbocyclic aromaticradicals having from 6 to 10 skeletal carbon atoms, mention may be madeof, for example, phenyl, biphenyl, naphthyl, phenanthrenyl andanthracenyl.

The imidazolidine radical (Im) usually has a structure of the generalformula (IIa) or (IIb),

where

-   R⁸, R⁹, R¹⁰, R¹¹ are identical or different and are each hydrogen,    straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,    C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate,    C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₀-aryloxy,    C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio, C₆-C₂₀-arylthio,    C₁-C₂₀-alkylsulphonyl, C₁-C_(ar) alkylsulphinyl.

alkylsulphonate, C₆-C₂₀-arylsulphonate or C₁-C₂₀-One or more of theradicals R⁸, R⁹, R¹⁰, R¹¹ can optionally be substituted, independentlyof one another, by one or more substituents, preferably straight-chainor branched C₁-C₁₀-alkyl, C₃-C₈-cycloalkyl, C₁-C₁₀-alkoxy orC₆-C₂₄-aryl, where these abovementioned substituents may in turn besubstituted by one or more radicals, preferably radicals selected fromthe group consisting of halogen, in particular chlorine or bromine,C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

In a preferred embodiment of the catalyst system used according to theinvention, at least one compound of the general formula (Z) is usedtogether with catalysts of the general formula (B) in which R⁸ and R⁹are each, independently of one another, hydrogen, C₆-C₂₄-aryl,particularly preferably phenyl, straight-chain or branched C₁-C₁₀-alkyl,particularly preferably propyl or butyl, or together with the carbonatoms to which they are bound form a cycloalkyl or aryl radical, whereall the abovementioned radicals may in turn optionally be substituted byone or more further radicals selected from the group consisting ofstraight-chain or branched C₁-C₁₀-alkyl, C₁-C₁₀-alkoxy, C₆-C₂₄-aryl anda functional group selected from the group consisting of hydroxy, thiol,thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro,carboxylic acid, disulphide, carbonate, isocyanate, carbodiimide,carboalkoxy, carbamate and halogen.

In a further preferred embodiment of the catalyst system used accordingto the invention, at least one compound of the general formula (Z) isused together with catalysts of the general formula (B) in which theradicals R¹⁰ and R¹¹ are identical or different and are eachstraight-chain or branched C₁-C₁₀-alkyl, particularly preferablyi-propyl or neopentyl, C₃-C₁₀-cycloalkyl, preferably adamantyl,C₆-C₂₄-aryl, particularly preferably phenyl, C₁-C₁₀-alkylsulphonate,particularly preferably methanesulphonate, or C₆-C₁₀-arylsulphonate,particularly preferably p-toluene sulphonate.

The abovementioned radicals as meanings of R¹⁰ and R¹¹ may optionally besubstituted by one or more further radicals selected from the groupconsisting of straight-chain or branched C₁-C₅-alkyl, in particularmethyl, C₁-C₅-alkoxy, aryl and a functional group selected from thegroup consisting of hydroxyl, thiol, thioether, ketone, aldehyde, ester,ether, amine, imine, amide, nitro, carboxylic acid, disulphide,carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate and halogen.

In particular, the radicals R¹⁰ and R¹¹ can be identical or differentand are each i-propyl, neopentyl, adamantyl or mesityl.

Particularly preferred imidazolidine radicals (Im) have theabovementioned structures (IIIa-IIIf), where Mes is in each case2,4,6-trimethylphenyl.

In the catalysts of the general formula (B), X¹ and X² are identical ordifferent and can each be, for example, hydrogen, halogen,pseudohalogen, straight-chain or branched C₁-C₃₀-alkyl, C₆-C₂₄-aryl,C₁-C₂₀-alkoxy, C₆-C₂₄-aryloxy, C₃-C₂₀-alkyldiketonate,C₆-C₂₄-aryldiketonate, C₁-C₂₀-carboxylate, C₁-C₂₀-alkylsulphonate,C₆-C₂₄-arylsulphonate, C₁-C₂₀-alkylthiol, C₆-C₂₄-arylthiol,C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl.

The abovementioned radicals X¹ and X² can also be substituted by one ormore further radicals, for example by halogen, preferably fluorine,C₁-C₁₀-alkyl, C₁-C₁₀-alkoxy or C₆-C₂₄-aryl radicals, where the latterradicals may also optionally be substituted by one or more substituentsselected from the group consisting of halogen, preferably fluorine,C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

In a preferred embodiment, X¹ and X² are identical or different and areeach halogen, in particular fluorine, chlorine, bromine or iodine,benzoate, C₁-C₅-carboxylate, C₁-C₅-alkyl, phenoxy, C₁-C₅-alkoxy,C₁-C₅-alkylthiol, C₆-C₂₄-arylthiol, C₆-C₂₄-aryl orC₁-C₅-alkylsulphonate.

In a particularly preferred embodiment, X¹ and X² are identical and areeach halogen, in particular chlorine, CF₃COO, CH₃COO, CFH₂COO, (CH₃)₃CO₃(CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO₃ PhO (phenoxy), MeO (methoxy), EtO(ethoxy), tosylate (p-CH₃—C₆H₄—SO₃), mesylate (2,4,6-trimethylphenyl) orCF₃SO₃ (trifluoromethanesulphonate).

In the general formula (B), the radical R¹ is an alkyl, cycloalkyl,alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy,alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl oralkylsulphinyl radical, which may all optionally be substituted by oneor more alkyl, halogen, alkoxy, aryl or heteroaryl radicals.

The radical R¹ is usually a C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-alkoxy,C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy,C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylamino, C₁-C₂₀-alkylthio,C₆-C₂₄-arylthio, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl radical,which can all optionally be substituted by one or more alkyl, halogen,alkoxy, aryl or heteroaryl radicals.

R¹ is preferably a C₃-C₂₀-cycloalkyl radical, a C₆-C₂₄-aryl radical or astraight-chain or branched C₁-C₃₀-alkyl radical, where the latter mayoptionally be interrupted by one or more double or triple bonds or oneor more heteroatoms, preferably oxygen or nitrogen. R¹ is particularlypreferably a straight-chain or branched C₁-C₁₂-alkyl radical.

The C₃-C₂₀-cycloalkyl radical is, for example, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl.

The C₁-C₁₂-alkyl radical can be, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl,2-methylbutyl, 3-methylbutyl, neopentyl, 1-ethylpropyl, n-hexyl,n-heptyl, n-octyl, n-decyl or n-dodecyl. In particular, R¹ is methyl orisopropyl.

The C₆-C₂₄-aryl radical is an aromatic radical having from 6 to 24skeletal carbon atoms. As preferred monocyclic, bicyclic or tricycliccarbocyclic aromatic radicals having from 6 to 10 skeletal carbon atoms,mention may be made of, for example, phenyl, biphenyl, naphthyl,phenanthrenyl and anthracenyl.

In the general formula (B), the radicals R², R³, R⁴ and R⁵ are identicalor different and can each be hydrogen, or an organic or inorganicradical.

In a useful embodiment, R², R³, R⁴, R⁵ are identical or different andare each hydrogen, halogen, nitro, CF₃, alkyl, cycloalkyl, alkenyl,alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl,alkylamino, alkylthio, arylthio, alkylsulphonyl or alkylsulphinyl, whichmay all optionally be substituted by one or more alkyl, alkoxy, halogen,aryl or heteroaryl radicals.

R², R³, R⁴, R⁵ are usually identical or different and are each hydrogen,halogen, preferably chlorine or bromine, nitro, CF₃, C₁-C₃₀-alkyl,C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy,C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylamino, C₁-C₂₀-alkylthio,C₆-C₂₄-arylthio, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl, whichmay all optionally be substituted by one or more C₁-C₃₀-alkyl,C₁-C₂₀-alkoxy, halogen, C₆-C₂₄-aryl or heteroaryl radicals.

In a particularly useful embodiment, R², R³, R⁴, R⁵ are identical ordifferent and are each nitro, straight-chain or branched C₁-C₃₀-alkyl,C₅-C₂₀-cycloalkyl, straight-chain or branched C₁-C₂₀-alkoxy orC₆-C₂₄-aryl, preferably phenyl or naphthyl. The C₁-C₃₀-alkyl andC₁-C₂₀-alkoxy radicals can optionally be interrupted by one or moredouble or triple bonds or one or more heteroatoms, preferably oxygen ornitrogen.

Furthermore, two or more of the radicals R², R³, R⁴ and R⁵ can bebridged via aliphatic or aromatic structures. For example, R³ and R⁴together with the carbon atoms to which they are bound in the benzenering of the formula (B) can form a few fused-on benzene ring, so that anaphthyl structure results.

In the general formula (B), the radical R⁶ is hydrogen or an alkyl,alkenyl, alkynyl or aryl radical. R⁶ is preferably hydrogen or aC₁-C₃₀-alkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl or C₆-C₂₄-aryl radical. R⁶is particularly preferably hydrogen.

Further suitable catalyst systems are those comprising at least onecompound of the general formula (Z) together with a catalyst of thegeneral formula (B1),

where

-   M, L, X¹, X², R¹, R², R³, R⁴ and R⁵ can have the general, preferred    and particularly preferred meanings given for the general formula    (B).

These catalyst systems preferably comprise the catalyst of the generalformula (B1) together with a compound of the general formula (Z) inwhich the BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂,BF₂(OC₂H₅), BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from thegroup consisting of water, diethyl ether, ethylamine, THF, n-propanol,formic acid, acetic acid, trifluoroacetic acid, trichloroacetic acid,sulphuric acid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

The catalysts of the general formula (B1) are known in principle from,for example, US 2002/0107138 A1 (Hoveyda et al.) and can be obtained bythe preparative methods indicated there.

Particular preference is given to catalyst systems comprising catalystsof the general formula (B1) in which

-   M is ruthenium,-   X¹ and X² are both halogen, in particular both chlorine,-   R¹ is a straight-chain or branched C₁-C₁₂ alkyl radical,-   R², R³, R⁴, R⁵ have the general and preferred meanings given for the    general formula (B) and-   L has the general and preferred meanings given for the general    formula (B).

Especial preference is given to catalyst systems comprising catalysts ofthe general formula (B1) in which

-   M is ruthenium,-   X¹ and X² are both chlorine,-   R¹ is an isopropyl radical,-   R², R³, R⁴, R⁵ are all hydrogen and-   L is a substituted or unsubstituted imidazolidine radical of the    formulae (IIa) or (IIb),

-   -   where    -   R⁸, R⁹, R¹⁰, R¹¹ are identical or different and are each        hydrogen, straight-chain or branched C₁-C₃₀-alkyl,        C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,        C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,        C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,        C₁-C₂₀-alkylthio, C₆-C₂₄-arylthio, C₁-C₂₀-alkylsulphonyl,        C₁-C₂₀-alkylsulphonate, C₆-C₂₄-arylsulphonate or        C₁-C₂₀-alkylsulphinyl, where the above-mentioned radicals may        each be substituted by one or more substituents, preferably        straight-chain or branched C₁-C₁₀-alkyl, C₃-C₈-cycloalkyl,        C₁-C₁₀-alkoxy or C₆-C₂₄-aryl, where these abovementioned        substituents may in turn also be substituted by one or more        radicals, preferably radicals selected from the group consisting        of halogen, in particular chlorine or bromine, C₁-C₅-alkyl,        C₁-C₅-alkoxy and phenyl.

Very particular preference is given to a catalyst system comprising atleast one compound of the general formula (Z) and a catalyst which comesunder the general structural formula (B1) and has the formula (VII),where Mes is in each case 2,4,6-trimethylphenyl.

This catalyst (VII) is also referred to as “Hoveyda catalyst” in theliterature.

Further suitable catalyst systems are those which comprise at least onecompound of the general formula (Z) together with a catalyst which comesunder the general structural formula (B1) and has one of the formulae(VIII), (IX), (X), (XI), (XII), (XIII), (XIV) and (XV) below, where Mesis in each case 2,4,6-trimethylphenyl.

A further catalyst system which can be used according to the inventioncomprises at least one compound of the general formula (Z) and acatalyst of the general formula (B2),

where

-   M, L, X¹, X², R¹ and R⁶ have the general and preferred meanings    given for the formula (B),-   the radicals R¹² are identical or different and have the general and    preferred meanings given for the radicals R², R³, R⁴ and R⁵ in the    formula (B), with the exception of hydrogen, and-   n is 0, 1, 2 or 3.

These catalyst systems preferably comprise the catalyst of the generalformula (B2) together with a compound of the general formula (Z) inwhich the BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂,BF₂(OC₂H₅), BR(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from thegroup consisting of water, diethyl ether, ethylamine, THF, n-propanol,formic acid, acetic acid, trifluoroacetic acid, trichloroacetic acid,sulphuric acid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

The catalysts of the general formula (B2) are known in principle from,for example, WO-A-2004/035596 (Greta) and can be obtained by thepreparative methods indicated there.

Particular preference is given to using catalyst systems comprising atleast one compound of the general formula (Z) and a catalyst of thegeneral formula (B2) in which

-   M is ruthenium,-   X¹ and X² are both halogen, in particular both chlorine,-   R¹ is a straight-chain or branched C₁-C₁₂ alkyl radical,-   R¹² has the meanings given for the general formula (B2),-   n is 0, 1, 2 or 3,-   R⁶ is hydrogen and-   L has the meanings given for the general formula (B).

Especial preference is given to using catalyst systems comprising atleast one compound of the general formula (Z) and a catalyst of thegeneral formula (B2) in which

-   M is ruthenium,-   X¹ and X² are both chlorine,-   R¹ is an isopropyl radical,-   n is 0 and-   L is a substituted or unsubstituted imidazolidine radical of the    formulae (Ha) or (IIb), where R⁸, R⁹, R¹⁰, R¹¹ are identical or    different and have the meanings given for the especially preferred    catalysts of the general formula (B1).

A particularly suitable catalyst system is a system comprising acatalyst of the structure (XVI) below and a compound of the generalformula (Z) in which the BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br,BFBr₂, BF₂(OC₂H₅), BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected fromthe group consisting of water, diethyl ether, ethylamine, THF,n-propanol, formic acid, acetic acid, trifluoroacetic acid,trichloroacetic acid, sulphuric acid, phosphoric acid,trifluoromethanesulphonic acid and toluenesulphonic acid and v=1, 2, 3,4 or 5, particularly preferably 1, 2 or 3.

The catalyst (XVI) is also referred to as “Grela catalyst” in theliterature.

A further suitable catalyst system comprises at least one compound ofthe general formula (Z) and a catalyst which comes under the generalformula (B2) and has the structure (XVII) below, where Mes is in eachcase 2,4,6-trimethylphenyl.

An alternative embodiment relates to catalyst systems comprising atleast one compound of the general formula (Z) and a dendritic catalystof the general formula (B3),

where D¹, D², D³ and D⁴ each have a structure of the general formula(XVIII) below which is bound via the methylene group shown at right tothe silicon of the formula (B3)

where

-   M, L, X¹, X², R¹, R², R³, R⁵ and R⁶ can have the general and    preferred meanings given for the general formula (B).

These catalyst systems preferably contain the catalyst of the generalformula (B3) together with a compound of the general formula (Z) inwhich the BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂,BF₂(OC₂H₅), BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from thegroup consisting of water, diethyl ether, ethylamine, THF, n-propanol,formic acid, acetic acid, trifluoroacetic acid, trichloroacetic acid,sulphuric acid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

The catalysts of the general formula (B3) are known from US 2002/0107138A1 and can be prepared according to the information given there.

A further alternative embodiment relates to the use of a catalyst systemcomprising at least one compound of the general formula (Z) and acatalyst of the formula (B4),

where the symbol  represents a support.

The support is preferably a poly(styrenedivinylbenzene) copolymer(PS-DVB). The catalysts of the formula (B4) are known in principle fromChem. Eur. J. 2004 10, 777-784 and can be obtained by preparativemethods described there.

All the abovementioned catalysts of type (B) can either be used as suchin the reaction mixture of the NBR metathesis or can be applied to andimmobilized on a solid support. Materials suitable as solid phases orsupports are materials which firstly are inert towards the reactionmixture of the metathesis and secondly do not impair the activity of thecatalyst. It is possible to use, for example, metals, glass, polymers,ceramic, organic polymer spheres or inorganic sol-gels, carbon black,silica, silicates, calcium carbonate and barium sulphate forimmobilizing the catalyst.

A further embodiment relates to the use of catalyst systems comprisingat least one compound of the general formula (Z) and a catalyst of thegeneral formula (C),

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different and are anionic ligands,-   the radicals R′ are identical or different and are organic radicals,-   Im is a substituted or unsubstituted imidazolidine radical and-   An is an anion.

These catalyst systems preferably contain the catalyst of the generalformula (C) together with a compound of the general formula (Z) in whichthe BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂, BF₂(OC₂H₅),BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from the groupconsisting of water, diethyl ether, ethylamine, THF, n-propanol, formicacid, acetic acid, trifluoroacetic acid, trichloroacetic acid, sulphuricacid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

The catalysts of the general formula (C) are known in principle (see,for example, Angew. Chem. Int. Ed. 2004, 43, 6161-6165).

X¹ and X² in the general formula (C) can have the same general,preferred and particularly preferred meanings as in the formulae (A) and(B).

The imidazolidine radical (Im) usually has a structure of one of thegeneral formulae (IIa) and (IIb) which have already been mentioned forthe catalyst type of the formulae (A) and (B) and can also have all thestructures mentioned as preferred there, in particular those of theformulae (IIIa)-(IIIf).

The radicals R′ in the general formula (C) are identical or differentand are each a straight-chain or branched C₁-C₃₀-alkyl,C₅-C₃₀-cycloalkyl or aryl radical, where the C₁-C₃₀-alkyl radicals mayoptionally be interrupted by one or more double or triple bonds or oneor more heteroatoms, preferably oxygen or nitrogen.

Aryl is an aromatic radical having from 6 to 24 skeletal carbon atoms.As preferred monocyclic, bicyclic or tricyclic carbocyclic aromaticradicals having from 6 to 10 skeletal carbon atoms, mention may be madeof, for example, phenyl, biphenyl, naphthyl, phenanthrenyl andanthracenyl.

The radicals R′ in the general formula (C) are preferably identical andare preferably each phenyl, cyclohexyl, cyclopentyl, isopropyl, o-tolyl,o-xylyl or mesityl.

A further alternative embodiment relates to the use of a catalyst systemcomprising at least one compound of the general formula (Z) and acatalyst of the general formula (D),

where

-   M is ruthenium or osmium,-   R¹³ and R¹⁴ are each, independently of one another, hydrogen,    C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,    C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,    C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,    C₁-C₂₀-alkylthio, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl,-   X³ is an anionic ligand,-   L² is an uncharged 7r-bonded ligand, either monocyclic or    polycyclic,-   L³ is a ligand from the group consisting of phosphines, sulphonated    phosphines, fluorinated phosphines, functionalized phosphines having    up to three aminoalkyl, ammonioalkyl, alkoxyalkyl,    alkoxycarbonylalkyl, hydrocarbonylalkyl, hydroxyalkyl or ketoalkyl    groups, phosphites, phosphinites, phosphonites, phosphinamines,    arsines, stibines, ethers, amines, amides, imines, sulphoxides,    thioethers and pyridines,-   Y is a noncoordinating anion and-   n is 0, 1, 2, 3, 4 or 5.

These catalyst systems preferably contain the catalyst of the generalformula (D) together with a compound of the general formula (Z) in whichthe BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂, BF₂(OC₂H₅),BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from the groupconsisting of water, diethyl ether, ethylamine, THF, n-propanol, formicacid, acetic acid, trifluoroacetic acid, trichloroacetic acid, sulphuricacid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

A further embodiment of the invention relates to the use of a catalystsystem comprising at least one compound of the general formula (Z) and acatalyst of the general formula (E),

whereM² is molybdenum or tungsten,R¹⁵ and R¹⁶ are identical or different and are each hydrogen,C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy,C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio,C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl,

-   R¹⁷ and R¹⁸ are identical or different and are each a substituted or    halogen-substituted C₁-C₂₀ alkyl, C₆-C₂₄-aryl, C₆-C₃₀-aralkyl    radical or a silicone-containing analogue thereof.

These catalyst systems preferably contain the catalyst of the generalformula (E) together with a compound of the general formula (Z) in whichthe BF_(m)X_(n) moiety is BF₃, BF₂Cl, BFCl₂, BF₂Br, BFBr₂, BF₂(OC₂H₅),BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from the groupconsisting of water, diethyl ether, ethylamine, THE, n-propanol, formicacid, acetic acid, trifluoroacetic acid, trichloroacetic acid, sulphuricacid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

A further alternative embodiment relates to the use of a catalyst systemcomprising at least one compound of the general formula (Z) and acatalyst of the general formula (F),

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different and are anionic ligands which    can have all the meanings of X¹ and X² given for the general    formulae (A) and (B),-   L represents identical or different ligands which can have all the    meanings of L given for the general formulae (A) and (B),-   R¹⁹ and R²⁰ are identical or different and are each hydrogen or    substituted or unsubstituted alkyl.

These catalyst systems preferably contain the catalyst of the generalformula (F) together with a compound of the general formula (Z) in whichthe BF_(m)X_(n) moiety is BF₃, BF₂C1, BFCl₂, BF₂Br, BFBr₂, BF₂(OC₂H₅),BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from the groupconsisting of water, diethyl ether, ethylamine, THF, n-propanol, formicacid, acetic acid, trifluoroacetic acid, trichloroacetic acid, sulphuricacid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3.

A further alternative embodiment relates to the use according to theinvention of a catalyst system comprising at least one compound of thegeneral formula (Z) and a catalyst of the general formula (G), (H) or(K),

where

-   M is osmium or ruthenium,-   X¹ and X² are identical or different and are two ligands, preferably    anionic ligands,-   L is a ligand, preferably an uncharged electron donor,-   Z¹ and Z² are identical or different and are uncharged electron    donors,-   R²¹ and R²² are each, independently of one another, hydrogen, alkyl,    cycloalkyl, alkenyl, alkynyl, aryl, carboxylate, alkoxy, alkenyloxy,    alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio,    alkylsulphonyl or alkylsulphinyl, each of which may be substituted    by one or more radicals selected from among alkyl, halogen, alkoxy,    aryl and heteroaryl.

The catalysts of the general formulae (G), (H) and (K) are known inprinciple, e.g. from WO 2003/011455 A1, WO 2003/087167 A2,Organometallics 2001, 20, 5314 and Angew. Chem. Int. Ed. 2002, 41, 4038.The catalysts are commercially available or can be synthesized by thepreparative methods indicated in the abovementioned literaturereferences.

Z¹ and Z²

In the catalyst systems which can be used according to the invention,use is made of catalysts of the general formulae (G), (H) and (K) inwhich Z¹ and Z² are identical or different and are uncharged electrondonors. These ligands are usually weakly coordinating. They aretypically optionally substituted heterocyclic groups. These can be 5- or6-membered monocyclic groups having from 1 to 4, preferably from 1 to 3and particularly preferably 1 or 2, heteroatoms or be bicyclic orpolycyclic structures made up of 2, 3, 4 or 5 such 5- or 6-memberedmonocyclic groups, where all the abovementioned groups may optionally besubstituted by one or more alkyl, preferably C₁-C₁₀-alkyl, cycloalkyl,preferably C₃-C₈-cycloalkyl, alkoxy, preferably C₁-C₁₀-alkoxy, halogen,preferably chlorine or bromine, aryl, preferably C₆-C₂₄-aryl, orheteroaryl, preferably C₅-C₂₃ heteroaryl radicals, which may each besubstituted in turn by one or more groups, preferably groups selectedfrom the group consisting of halogen, in particular chlorine or bromine,C₁-C₅-alkyl, C₁-C₅-alkoxy and phenyl.

Examples of Z¹ and Z² encompass nitrogen-containing heterocycles such aspyridines, pyridazines, bipyridines, pyrimidines, pyrazines,pyrazolidines, pyrrolidines, piperazines, indazoles, quinolines,purines, acridines, bisimidazoles, picolylimines, imidazolidines andpyrroles.

Z¹ and Z² can also be bridged with one another to form a cyclicstructure. In this case, Z¹ and Z² form a single bidentate ligand.

L

In the catalysts of the general formulae (G), (H) and (K), L can havethe same general, preferred and particularly preferred meanings as L inthe general formulae (A) and (B).

R²¹ and R²²

In the catalysts of the general formulae (G), (H) and (K), R²¹ and R²²are identical or different and are each alkyl, preferably C₁-C₃₀-alkyl,particularly preferably C₁-C₂₀-alkyl, cycloalkyl, preferablyC₃-C₂₀-cycloalkyl, particularly preferably C₃-C₈-cycloalkyl, alkenyl,preferably C₂-C₂₀-alkenyl, particularly preferably C₂-C₁₆-alkenyl,alkynyl, preferably C₂-C₂₀-alkynyl, particularly preferablyC₂-C₁₆-alkynyl, aryl, preferably C₆-C₂₄-aryl, carboxylate, preferablyC₁-C₂₀-carboxylate, alkoxy, preferably C₁-C₂₀-alkoxy, alkenyloxy,preferably C₂-C₂₀-alkenyloxy, alkynyloxy, preferably C₂-C₂₀-alkynyloxy,aryloxy, preferably C₆-C₂₄-aryloxy, alkoxycarbonyl, preferablyC₂-C₂₀-alkoxycarbonyl, alkylamino, preferably C₁-C₃₀-alkylamino,alkylthio, preferably C₁-C₃₀-alkylthio, arylthio, preferablyC₆-C₂₄-arylthio, alkylsulphonyl, preferably C₁-C₂₀-alkylsulphonyl, oralkylsulphinyl, preferably C₁-C₂₀-alkylsulphinyl, where theabovementioned substituents may be substituted by one or more alkyl,halogen, alkoxy, aryl or heteroaryl radicals.

X¹ and X²

In the catalysts of the general formulae (G), (H) and (K), X¹ and X² areidentical or different and can have the same general, preferred andparticularly preferred meanings as given above for X¹ and X² in thegeneral formula (A).

Preference is given to using catalysts of the general formulae (G), (H)and (K) in which

-   M is ruthenium,-   X¹ and X² are both halogen, in particular chlorine,-   R¹ and R² are identical or different and are 5- or 6-membered    monocyclic groups having from 1 to 4, preferably from 1 to 3 and    particularly preferably 1 or 2, heteroatoms or bicyclic or    polycyclic structures made up of 2, 3, 4 or 5 such 5- or 6-membered    monocyclic groups, where all the abovementioned groups may be    substituted by one or more alkyl, preferably C₁-C₁₀-alkyl,    cycloalkyl, preferably C₃-C₈-cycloalkyl, alkoxy, preferably    C₁-C₁₀-alkoxy, halogen, preferably chlorine or bromine, aryl,    preferably C₆-C₂₄-aryl, or heteroaryl, preferably C₅-C₂₃-heteroaryl    radicals,-   R²¹ and R²² are identical or different and are each C₁-C₃₀-alkyl,    C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl,    C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,    C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl,    C₁-C₃₀-alkylamino, C₁-C₃₀-alkylthio, C₆-C₂₄-arylthio,    C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphinyl and-   L has a structure of one of the above-described general formulae    (IIa) and (Lib), in particular the formulae (IIIa) to (IIIf).

A particularly preferred catalyst which comes under the general formula(G) has the structure (XIX),

where

-   R²³ and R²⁴ are identical or different and are each halogen,    straight-chain or branched C₁-C_(m)-alkyl, C₁-C₂₀-heteroalkyl,    C₁-C₁₀-haloalkyl, C₁-C₁₀-alkoxy, C₆-C₂₄-aryl, preferably phenyl,    formyl, nitro, a nitrogen heterocycle, preferably pyridine,    piperidine or pyrazine, carboxy, alkylcarbonyl, halocarbonyl,    carbamoyl, thiocarbamoyl, carbamido, thioformyl, amino,    dialkylamino, trialkylsilyl or trialkoxysilyl.

The abovementioned radicals C₁-C₂₀-alkyl, C₁-C₂₀-heteroalkyl,C₁-C₁₀-haloalkyl, C₁-C₁₀-alkoxy, C₆-C₂₄-aryl, preferably phenyl, formyl,nitro, a nitrogen heterocycle, preferably pyridine, piperidine orpyrazine, carboxy, alkylcarbonyl, halocarbonyl, carbamoyl,thiocarbamoyl, carbamido, thioformyl, amino, trialkylsilyl andtrialkoxysilyl may each in turn be substituted by one or more halogen,preferably fluorine, chlorine or bromine, C₁-C₅-alkyl, C₁-C₅-alkoxy orphenyl radicals.

Particularly preferred embodiments of the catalyst of the formula (XIX)have the structure (XIX a) or (XIX b), where R²³ and R²⁴ have the samemeanings as given for the formula (XIX).

When R²³ and R²⁴ are each hydrogen, the compound is referred to as“Grubbs III catalyst” in the literature.

Further suitable catalysts which come under the general formulae (G),(H) and (K) have the structural formulae (XX)-(XXXI) below, where Mes isin each case 2,4,6-trimethylphenyl.

A further alternative embodiment relates to the use according to theinvention of a catalyst system comprising at least one compound of thegeneral formula (Z) and a catalyst (N) which has the general structuralelement (N1),

where the carbon atom denoted by “*” is bound via one or more doublebonds to the basic catalyst frameworkand

-   R²⁵-R³² are identical or different and are each hydrogen, halogen,    hydroxyl, aldehyde, keto, thiol, CF₃, nitro, nitroso, cyano,    thiocyano, isocyanato, carbodiimide, carbamate, thiocarbamate,    dithiocarbamate, amino, amido, imino, silyl, sulphonate (—SO₃ ⁻),    —OSO₃ ⁻, —PO₃ ⁻ or OPO₃ ⁻ or alkyl, cycloalkyl, alkenyl, alkynyl,    aryl, carboxylate, alkoxy, alkenyloxy, alkynyloxy, aryloxy,    alkoxycarbonyl, alkylamino, alkylthio, arylthio, alkylsulphonyl,    alkylsulphinyl, dialkylamino, alkylsilyl or alkoxysilyl, where these    radicals can all optionally be substituted by one or more alkyl,    halogen, alkoxy, aryl or heteroaryl radicals, or alternatively two    directly adjacent radicals from the group consisting of R²⁵-R³² can    be bridged with inclusion of the ring carbons to which they are    bound to form a cyclic group, preferably an aromatic system, or    alternatively R⁸ may be bridged to another ligand of the ruthenium-    or osmium-carbene complex catalyst,-   m is 0 or 1 and-   A is oxygen, sulphur, C(R³³R³⁴), N—R³⁵, —C(R³⁶)═C(R³⁷)—,    —C(R³⁶)(R³⁸)—C(R³⁷)(R³⁹)—, where R³³-R³⁹ are identical or different    and can each have the same meanings as the radicals R²⁵-R³².

The catalysts to be used according to the invention in the catalystsystems have the structural element of the general formula (N1), wherethe carbon atom denoted by “*” is bound via one or more double bonds tothe basic catalyst framework. If the carbon atom denoted by “*” is boundvia two or more double bonds to the basic catalyst framework, thesedouble bonds can be cumulated or conjugated.

Such catalysts (N) have been described in the as yet unpublished Germanpatent application number DE 102007039695, which is hereby incorporatedby reference for the definition of the catalysts (N) and theirpreparation, in so far as this is permitted by the applicablejurisdictions.

The catalysts (N) having a structural element of the general formula(N1) include, for example, those of the general formulae (N2a) and (N2b)below,

where

-   M is ruthenium or osmium,-   X¹ and X² are identical or different and are two ligands, preferably    anionic ligands.-   L¹ and L² are identical or different ligands, preferably uncharged    electron donors, where L² can, as an alternative, also be bridged    with the radical R⁸,-   n is 0, 1, 2 or 3, preferably 0, 1 or 2,-   n′ is 1 or 2, preferably 1, and

R²⁵-R³², m and A have the same meanings as in the general formula (N)).

In the catalysts of the general formula (N2a), the structural element ofthe general formula (N1) is bound via a double bond (n=0) or via 2, 3 or4 cumulated double bonds (in the case of n=1, 2 or 3) to the centralmetal of the complex catalyst. In the catalysts according to theinvention of the general formula (N2b), the structural element of thegeneral formula (N1) is bound via conjugated double bonds to the metalof the complex catalyst. In both cases, a double bond in the directionof the central metal of the complex catalyst is located on the carbonatom denoted by “*”.

The catalysts of the general formulae (N10a) and (N10b) thus comprisecatalysts in which the general structural elements (N3)-(N9)

are bound via the carbon atom denoted by “*” via one or more doublebonds to the basic catalyst framework of the general formula (N10a) or(N10b)

where X¹ and X², L¹ and L², n, n′ and R²⁵-R³⁹ have the meanings givenfor the general formulae (N2a) and (N2b).

The ruthenium- or osmium-carbene catalysts according to the inventionare typically pentacoordinated.

In the Structural Element of the General Formula (N1),

-   R¹⁵-R³² are identical or different and are each hydrogen, halogen,    hydroxyl, aldehyde, keto, thiol, CF₃, nitro, nitroso, cyano,    thiocyano, isocyanato, carbodiimide, carbamate, thiocarbamate,    dithiocarbamate, amino, amido, imino, silyl, sulphonate (—SO₃ ⁻),    —OSO₃ ⁻, —PO₃ ⁻ or OPO₃ ⁻ or alkyl, preferably C₁-C_(m)-alkyl, in    particular C₁-C₆-alkyl, cycloalkyl, preferably C₃-C₂₀-cycloalkyl, in    particular C₃-C₈-cycloalkyl, alkenyl, preferably C₂-C₂₀-alkenyl,    alkynyl, preferably C₂-C₂₀-alkynyl, aryl, preferably C₆-C₂₄-aryl, in    particular phenyl, carboxylate, preferably C₁-C₂₀-carboxylate,    alkoxy, preferably C₁-C₂₀-alkoxy, alkenyloxy, preferably    C₂-C₂₀-alkenyloxy, alkynyloxy, preferably C₂-C₂₀-alkynyloxy,    aryloxy, preferably C₆-C₂₄-aryloxy, alkoxycarbonyl, preferably    C₂-C₂₀-alkoxycarbonyl, alkylamino, preferably C₁-C₃₀-alkylamino,    alkylthio, preferably C₁-C₃₀-alkylthio, arylthio, preferably    C₆-C₂₄-arylthio, alkylsulphonyl, preferably C₁-C₂₀-alkylsulphonyl,    alkylsulphinyl, preferably C₁-C₂₀-alkylsulphinyl, dialkylamino,    preferably di(C₁-C₂₀-alkyl)amino, alkylsilyl, preferably    C₁-C₂₀-alkylsilyl, or alkoxysilyl, preferably C₁-C₂₀-alkoxysilyl,    where these radicals may all optionally be substituted by one or    more alkyl, halogen, alkoxy, aryl or heteroaryl radicals, or    alternatively two directly adjacent radicals from the group    consisting of R²⁵-R³² can also be bridged with inclusion of the ring    carbons to which they are bound to form a cyclic group, preferably    an aromatic system, or alternatively R⁸ may be bridged with another    ligand of the ruthenium- or osmium-carbene complex catalyst,-   m is 0 or 1 and-   A is oxygen, sulphur, C(R³³)(R³⁴), N—R³⁵, —C(R³⁶)═C(R³⁷)— or    —C(R³⁶)(R³⁸)—C(R³⁷)(R³⁹)—, where R³³-R³⁹ are identical or different    and can each have the same preferred meanings as the radicals R¹-R⁸.

C₁-C₆-alkyl in the structural element of the general formula (N1) is,for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,neopentyl, 1-ethylpropyl or n-hexyl.

C₃-C₈-cycloalkyl in the structural element of the general formula (N1)is, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cycloheptyl or cyclooctyl.

C₆-C₂₄-aryl in the structural element of the general formula (N1) is anaromatic radical having from 6 to 24 skeletal carbon atoms. As preferredmonocyclic, bicyclic or tricyclic carbocyclic aromatic radicals havingfrom 6 to 10 skeletal carbon atoms, mention may be made of, for example,phenyl, biphenyl, naphthyl, phenanthrenyl and anthracenyl.

The radicals X¹ and X² in the structural element of the general formula(N1) have the same general, preferred and particularly preferredmeanings given for catalysts of the general formula A.

In the general formulae (N2a) and (N2b) and analogously in the generalformulae (N10a) and (N10b), the radicals L¹ and L² are identical ordifferent ligands, preferably uncharged electron donors, and can havethe same general, preferred and particularly preferred meanings givenfor the catalysts of the general formula A.

Preference is given to using catalysts of the general formulae (N2a) and(N2b) having a general structural unit (N1) in which

-   M is ruthenium,-   X¹ and X² are both halogen,-   n is 0, 1 or 2 in the general formula (N2a) or-   n′ is 1 in the general formula (N2b),-   L¹ and L² are identical or different and have the general or    preferred meanings given for the general formulae (N2a) and (N2b),-   R²⁵-R³² are identical or different and have the general or preferred    meanings given for the general formulae (N2a) and (N2b),-   m is either 0 or 1    and, when m=1-   A is oxygen, sulphur, C(C₁-C₁₀-alkyl)₂,    —C(C₁-C₁₀-alkyl)₂—C(C₁-C₁₀-alkyl)₂—,    —C(C₁-C₁₀-alkyl)=C(C₁-C₁₀-alkyl)- or N(C₁-C₁₀-alkyl).

Very particular preference is given to using catalysts of the formulae(N2a) or (N2b) having a general structural unit (N1) in which

-   M is ruthenium,-   X¹ and X² are both chlorine,-   n is 0, 1 or 2 in the general formula (N2a) or-   n′ is 1 in the general formula (N2b),-   L¹ is an imidazolidine radical of one of the formulae (Ma) to JIM,-   L² is a sulphonated phosphine, phosphate, phosphinite, phosphonite,    arsine, stibine, ether, amine, amide, sulphoxide, carboxyl,    nitrosyl, pyridine radical, an imidazolidine radical of one of the    formulae (XIIa) to (XIIf) or a phosphine ligand, in particular PPh₃,    P(p-tol)₃, P(o-tol)₃, PPh(CH₃)₂, P(CF₃)₃, P(p-FC₆H₄)₃,    P(p-CF₃C₆H₄)₃, P(C₆H₄—SO₃Na)₃, P(CH₂C₆H₄—SO₃Na)₃, P(isopropyl)₃,    P(CHCH₃(CH₂CH₃))₃, P(cyclopentyl)₃, P(cyclohexyl)₃, P(neopentyl)₃    and P(neophenyl)₃,-   R²⁵-R³² have the general or preferred meanings given for the general    formulae (N2a) and (N2b),-   m is either 0 or 1    and, when m=1,-   A is oxygen, sulphur, C(C₁-C₁₀-alkyl)₂, —C(C₁-C₁₀-alkyl)₂,    —C(C₁-C₁₀-alkyl)₂—, —C(C₁-C₁₀-alkyl)=C(C₁-C₁₀-alkyl)- or    N(C₁-C₁₀-alkyl).

If the radical R²⁵ is bridged with another ligand of the catalyst of theformula N, this results, for example, in the case of the catalysts ofthe general formulae (N2a) and (N2b) in the following structures of thegeneral formulae (N13a) and (N13b)

where

-   Y¹ is oxygen, sulphur, an N—R⁴¹ radical or a P—R⁴¹ radical, where    R^(4I) has the following meanings,-   R⁴⁰ and R⁴¹ are identical or different and are each an alkyl,    cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy, alkynyloxy,    aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio,    alkylsulphonyl or alkylsulphinyl radical, which may all optionally    be substituted by one or more alkyl, halogen, alkoxy, aryl or    heteroaryl radicals,-   p is 0 or 1 and-   Y² where p=1 is, —(CH₂)_(r)— where r=1, 2 or 3, —C(═O)—CH₂—,    —C(═O)—, —N═CH—, —N(H)—C(═O)— or alternatively the total structural    unit “—Y¹(R⁴⁰)—(Y²)_(p)—” is (—N(R⁴⁰)═CH—CH₂—),    (—N(R⁴⁰,R⁴¹)═CH—CH₂—) and-   where M, X¹, X², L¹, R²⁵-R³², A, m and n have the same meanings as    in the general formulae (IIa) and (IIb).

Preferred catalyst systems contain a compound of the general formula (Z)in which the BF_(m)X_(n) moiety is BF₃, BF₂O, BFCl₂ BF₂Br, BFBr₂,BF₂(OC₂H₅), BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂, D is selected from thegroup consisting of water, diethyl ether, ethylamine, THF, n-propanol,formic acid, acetic acid, trifluoroacetic acid, trichloroacetic acid,sulphuric acid, phosphoric acid, trifluoromethanesulphonic acid andtoluenesulphonic acid and v=1, 2, 3, 4 or 5, particularly preferably 1,2 or 3, together with a catalyst of the formula (N) having one of thestructures shown below.

Catalysts (N) can be prepared by reaction of suitable catalyst precursorcomplexes with suitable diazo compounds when this synthesis is carriedout in a specific temperature range and at the same time the molar ratioof the starting materials is in a selected range. For this purpose, acatalyst precursor compound is, for example, reacted with a compound ofthe general formula (N1-Azo)

where R²⁵-R³², m and A have the meanings given for the general formula(NI), with this reaction being carried out

-   (i) at a temperature in the range from −20° C. to 100° C.,    preferably in the range from +10° C. to +80° C., particularly    preferably in the range from +30 to +50° C., and-   (ii) at a molar ratio of the catalyst precursor compound to the    compound of the general formula (N-1-Azo) of from 1:0.5 to 1:5,    preferably from 1:1.5 to 1:2.5, particularly preferably 1:2.

The compounds of the general formula (N1-Azo) are 9-diazofluorene orvarious derivatives thereof depending on the meanings of the radicalsR²⁵-R³² and A. It is possible to use a variety of derivatives of9-diazofluorene. In this way, a wide variety of fluorenylidenederivatives can be obtained.

The catalyst precursor compounds are ruthenium or osmium complexcatalysts which do not yet contain any ligand having the generalstructural element (N1).

In this reaction, a ligand leaves the catalyst precursor compound and acarbene ligand containing the general structural element (N1) is takenup.

The reaction can be carried out using saturated, unsaturated andaromatic hydrocarbons, ethers and halogenated solvents. Preference isgiven to chlorinated solvents such as dichloromethane,1,2-dichloroethane or chlorobenzene. The catalyst precursor compound inthe form of the ruthenium or osmium precursor is usually initiallycharged in a preferably dried solvent. The concentration of theruthenium or osmium precursor in the solvent is usually in the rangefrom 15 to 25% by weight, preferably in the range from 50 to 20% byweight. The solution can subsequently be heated. It has been found to beparticularly useful to heat the solution to a temperature in the rangefrom 30 to 50° C. The compound of the general formula (N-1-Azo) in ausually dried, preferably water-free solvent is then added. Theconcentration of the compound of the general formula (N1-Azo) in thesolvent is preferably in the range from 5 to 15% by weight, preferablyabout 10%. To complete the reaction, the mixture is allowed to reactfurther for from 0.5 h to 1.5 h at a temperature which is particularlypreferably in the same range as mentioned above, i.e. from 30 to 50° C.The solvent is subsequently removed and the residue is purified byextraction, for example with a mixture of hexane with an aromaticsolvent.

The catalyst according to the invention is usually not obtained in pureform but in an equimolar, determined by the stochiometry of thereaction, mixture with the reaction product of the compound of thegeneral formula (N1-Azo) with the leaving ligand of the catalystprecursor compound used in the reaction. The leaving ligand ispreferably a phosphine ligand. This reaction product can be removed inorder to obtain the pure catalyst according to the invention. However,metathesis reactions can be catalysed using not only the pure catalystaccording to the invention but also the mixture of this catalystaccording to the invention with the abovementioned reaction product.

The above-described process is described in more detail below:

In the case of the catalysts of the general formulae (N2a) and (N2b), acatalyst precursor compound of the general formula (“N2 precursor”),

where

-   M, X¹, X², L¹ and L² have the same general and preferred meanings as    in the general formulae (N2a) and (N2b) and-   LL is a “leaving ligand” and can have the same meanings as L' and L²    in the general formulae (N2a) and (N2b), preferably a phosphine    ligand having one of the meanings given for the general formulae    (N2a) and (N2b),    is reacted with a compound of the general formula (N1-Azo) at a    temperature in the range from −20° C. to 100° C., preferably in the    range from +10° C. to +80° C., particularly preferably in the range    from +30 to +50° C., and at a molar ratio of the catalyst precursor    compound of the general formula (XVII) to the compound of the    general formula (N1-Azo) of from 1:0.5 to 1:5, preferably from 1:1.5    to 1:2.5, particularly preferably 1:2. Further examples of the    preparation of such catalysts of the formula (N) are given in the as    yet unpublished patent application DE 102007039695.

In the catalyst system to be used according to the invention, themetathesis catalyst and the compound of the general formula (Z) are usedin a molar ratio of [metathesis catalyst:compound of the general formula(Z)]=1:(0.1-1000), preferably 1:(0.5-100) and particularly preferably 1:(1-50).

In the use according to the invention of the catalyst system in themetathesis reaction of nitrile rubbers, the compound of the generalformula (Z) can be added in a solvent or dispersion medium or withoutsolvent or dispersion medium to the complex catalyst or its solution inorder to obtain the catalyst system according to the invention.

As solvent or dispersion medium in which the compound of the generalformula (Z) is added to the complex catalyst or its solution, it ispossible to use all known solvents or dispersion media. For the additionof the compound of the general formula (Z) to be effective, it is notnecessary for the compound of the general formula (Z) to be soluble inthe dispersion medium. Preferred solvents or dispersion media include,but are not restricted to, acetone, benzene, chlorobenzene, chloroform,cyclohexane, dichloromethane, diethyl ether, dioxane, dimethylformamide,dimethylacetamide, dimethylsulphone, dimethyl sulphoxide, methyl ethylketone, tetrahydrofuran, tetrahydropyran and toluene. The solvent ordispersion medium is preferably inert towards the complex catalyst.

The abovementioned catalyst systems are, according to the invention,used for the metathesis of nitrile rubber. Their use according to theinvention is then a process for reducing the molecular weight of thenitrile rubber by bringing the nitrile rubber into contact with thecatalyst system of the invention. This reaction is a cross-metathesis.

In the use according to the invention of the catalyst systems for themetathesis of nitrile rubber, the amount in which the compound of thegeneral formula (Z) is used, based on the nitrile rubber to be degraded,is in the range from 0.0001 phr to 5 phr, preferably from 0.001 phr to 2phr (phr=parts by weight per 100 parts by weight of rubber).

For use in the NBR metathesis, too, the compound of the general formula(Z) can be added in a solvent or dispersion medium or without solvent ordispersion medium to a solution of the complex catalyst. As analternative, the compound of the general formula (Z) can also be addeddirectly to a solution of the nitrile rubber to be degraded to which thecomplex catalyst is also added, so that the entire catalyst systemaccording to the invention is present in the reaction mixture.

The amount of complex catalyst based on the nitrile rubber used dependson the nature and the catalytic activity of the specific complexcatalyst. The amount of complex catalyst used is usually from 1 to 1000ppm of noble metal, preferably from 2 to 500 ppm, in particular from 5to 250 ppm, based on the nitrile rubber used.

The NBR metathesis can be carried out in the absence or presence of acoolefin. This coolefin is preferably a straight-chain or branchedC₂-C₁₆-olefin. Suitable coolefins are, for example, ethylene, propylene,isobutene, styrene, 1-hexene and 1-octene. Preference is given to using1-hexene or 1-octene. If the coolefin is liquid (as in the case of, forexample, 1-hexene), the amount of coolefin is preferably in the range0.2-20% by weight, based on the nitrile rubber used. If the coolefin isa gas, as in the case of, for example, ethylene, the amount of coolefinis selected so that a pressure in the range 1×10⁵ Pa-1×10⁷ Pa,preferably a pressure in the range from 5.2×10⁵ Pa to 4×10⁶ Pa, isestablished in the reaction vessel at room temperature.

The metathesis reaction can be carried out in a suitable solvent whichdoes not deactive the catalyst used and also does not have an adverseeffect on the reaction in any other way. Preferred solvents include, butare not restricted to, dichloromethane, benzene, toluene, methyl ethylketone, acetone, tetrahydrofuran, tetrahydropyran, dioxane, cyclohexaneand chlorobenzene. The particularly preferred solvent is chlorobenzene.In some cases when the coolefin itself can function as solvent, e.g. inthe case of 1-hexene, the addition of a further additional solvent canbe dispensed with.

The concentration of the nitrile rubber used in the reaction mixture ofthe metathesis is not critical, but it should naturally be ensured thatthe reaction is not adversely affected by an excessively high viscosityof the reaction mixture and the associated mixing problems. Theconcentration of NBR in the reaction mixture is preferably in the rangefrom 1 to 25% by weight, particularly preferably in the range from 5 to20% by weight, based on the total reaction mixture.

The metathetic degradation is usually carried out at a temperature inthe range from 10° C. to 150° C., preferably at a temperature in therange from 20 to 100° C.

The reaction time depends on a number of factors, for example on thetype of NBR, the type of catalyst, the catalyst concentration used andthe reaction temperature. The reaction is typically complete within fivehours under normal conditions. The progress of the metathesis can bemonitored by standard analytical methods, e.g. by GPC measurements or bydetermination of the viscosity.

As nitrile rubbers (“NBR”), it is possible to use copolymers orterpolymers which contain repeating units of at least one conjugateddiene, at least one a,13-unsaturated nitrile and, if appropriate, one ormore further copolymerizable monomers in the metathesis reaction.

The conjugated diene can be of any nature. Preference is given to using(C₄-C₆)-conjugated dienes. Particular preference is given to1,3-butadiene, isoprene, 2,3-dimethylbutadiene, piperylene or mixturesthereof. In particular, use is made of 1,3-butadiene or isoprene ormixtures thereof. Very particular preference is given to 1,3-butadiene.

As α,β-unsaturated nitrile, it is possible to use any knownα,β-unsaturated nitrile, with preference being given to(C₃-C₅)-α,β-unsaturated nitriles such as acrylonitrile,methacrylonitrile, ethacrylonitrile or mixtures thereof. Particularpreference is given to acrylonitrile.

A particularly preferred nitrile rubber is thus a copolymer ofacrylonitrile and 1,3-butadiene.

In addition to the conjugated diene and the 4-unsaturated nitrile, it ispossible to use one or more further copolymerizable monomers known tothose skilled in the art, e.g. α,β-unsaturated monocarboxylic ordicarboxylic acids, their esters or amides. As α,β-unsaturatedmonocarboxylic or dicarboxylic acids, preference is given to fumaricacid, maleic acid, acrylic acid and methacrylic acid. As esters ofα,β-unsaturated carboxylic acids, preference is given to using theiralkyl esters and alkoxyalkyl esters. Particularly preferred alkyl estersof α,β-unsaturated carboxylic acids are methyl acrylate, ethyl acrylate,butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexylmethacrylate and octyl acrylate. Particularly preferred alkoxyalkylesters of α,β-unsaturated carboxylic acids aremethoxyethyl(meth)acrylate, ethoxyethyl(meth)acrylate andmethoxyethyl(meth)acrylate. It is also possible to use mixtures of alkylesters, e.g. those mentioned above, with alkoxyalkyl esters, e.g. in theform of those mentioned above.

The proportions of conjugated diene and α,β-unsaturated nitrile in theNBR polymers to be used can vary within wide ranges. The proportion ofthe conjugated diene or the sum of conjugated dienes is usually in therange from 40 to 90% by weight, preferably in the range from 60 to 85%by weight, based on the total polymer. The proportion of the4-unsaturated nitrile or the sum of α,β-unsaturated nitriles is usuallyfrom 10 to 60% by weight, preferably from 15 to 40% by weight, based onthe total polymer. The proportions of the monomers in each case add upto 100% by weight. The additional monomers can be present in amounts offrom 0 to 40% by weight, preferably from 0.1 to 40% by weight,particularly preferably from 1 to 30% by weight, based on the totalpolymer. In this case, corresponding proportions of the conjugated dieneor dienes and/or the α,β-unsaturated nitrile or nitriles are replaced byproportions of the additional monomers, with the proportions of allmonomers in each case adding up to 100% by weight.

The preparation of the nitrite rubbers by polymerization of theabovementioned monomers is adequately known to those skilled in the artand is comprehensively described in the literature.

Nitrile rubbers which can be used for the purposes of the invention arealso commercially available, e.g. as products from the product range ofthe Perbunan® and Krynac® grades of Lanxess Deutschland GmbH.

The nitrile rubbers used for the metathesis have a Mooney viscosity (ML1+4 at 100° C.) in the range from 30 to 70, preferably from 30 to 50.This corresponds to a weight average molecular weight M_(w) in the range150 000-500 000, preferably in the range 180 000-400 000. Furthermore,the nitrile rubbers used have a polydispersity PDI=M_(w)/M_(n), whereM_(w) is the weight average molecular weight and M_(n) is the numberaverage molecular weight, in the range 2.0-6.0 and preferably in therange 2.0-4.0.

The determination of the Mooney viscosity is carried out n accordancewith ASTM Standard D 1646.

The nitrile rubbers obtained by the metathesis process of the inventionhave a Mooney viscosity (ML 1+4 at 100° C.) in the range 5-30,preferably in the range 5-20. This corresponds to a weight averagemolecular weight M, in the range 10 000-100 000, preferably in the range10 000-80 000. Furthermore, the nitrile rubbers obtained have apolydispersity PDI=M_(w)/M_(n), where M_(n) is the number averagemolecular weight and M_(w) is the weight average molecular weight, inthe range 1.4-4.0, preferably in the range 1.5-3.0.

The metathetic degradation in the presence of the catalyst system of theinvention can be followed by a hydration of the degraded nitrile rubbersobtained. This can be carried out in a manner known to those skilled inthe art.

The hydration can be carried out using homogeneous or heterogeneoushydration catalysts. It is also possible to carry out the hydration insitu, i.e. in the same reaction mixture in which the metatheticdegradation has previously taken place and without the need to isolatethe degraded nitrile rubber. The hydration catalyst is simply introducedinto the reaction vessel.

The catalysts used are usually based on rhodium, ruthenium or titanium,but it is also possible to use platinum, iridium, palladium, rhenium,ruthenium, osmium, cobalt or copper either as metal or preferably in theform of metal compounds (see, for example, U.S. Pat. No. 3,700,637,DE-A-25 39 132, EP-A-0 134 023, DE-A-35 41 689, DE-A-35 40 918, EP-A-0298 386, DE-A-35 29 252, DE-A-34 33 392, U.S. Pat. No. 4,464,515 andU.S. Pat. No. 4,503,196).

Suitable catalysts and solvents for a hydration in the homogeneous phaseare described below and are also known from DE-A-25 39 132 and EP-A-0471 250.

The selective hydration can, for example, be achieved in the presence ofa rhodium- or ruthenium-containing catalyst. It is possible to use, forexample, a catalyst of the general formula

(R¹ _(m)BP)₁M X_(n),

where M is ruthenium or rhodium is, the radicals R¹ are identical ordifferent and are each a C₁-C₈-alkyl group, a C₄-C₈-cycloalkyl group, aC₆-C₁₅-aryl group or a C₇-C₁₅-aralkyl group. B is phosphorus, arsenic,sulphur or a sulphoxide group S═O, X is hydrogen or an anion, preferablyhalogen and particularly preferably chlorine or bromine, 1 is 2, 3 or 4,m is 2 or 3 and n is 1, 2 or 3, preferably 1 or 3. Preferred catalystsare tris(triphenylphosphine)rhodium(I) chloride,tris(triphenylphosphine)rhodium(III) chloride andtris(dimethylsulphoxide)rhodium(III) chloride and alsotetrakis(triphenylphosphine)rhodium hydride of the formula (C₆H₅)₃P)₄RhHand the corresponding compounds in which all or part of thetriphenylphosphine has been replaced by tricyclohexylphosphine. Thecatalyst can be used in small amounts. An amount in the range 0.01-1% byweight, preferably in the range 0.03 to 0.5% by weight and particularlypreferably in the range 0.1-0.3% by weight, based on the weight of thepolymer, is suitable.

It is usually useful to use the catalyst together with a cocatalystwhich is a ligand of the formula R¹ _(m)B, where R¹, m and B have themeanings given above for the catalyst. Preference is given to m being 3,B being phosphorus and the radicals R¹ can be identical or different.The cocatalysts preferably have trialkyl, tricycloalkyl, triaryl,triaralkyl, diarylmonoalkyl, diarylmonocycloalkyl, dialkylmonoaryl,dialkylmonocycloalkyl, dicycloalkylmonoaryl or dicyclalkylmonoarylradicals.

Examples of cocatalysts may be found, for example, in U.S. Pat. No.4,631,315. A preferred cocatalyst is triphenylphosphine. The cocatalystis preferably used in amounts in the range 0.1-5% by weight, preferablyin the range 0.3-4% by weight, based on the weight of the nitrile rubberto be hydrated. Furthermore, the weight ratio of the rhodium-containingcatalyst to the cocatalyst is preferably in the range from 1:3 to 1:55,particularly preferably in the range from 1:5 to 1:45. Based on 100parts by weight of the nitrite rubber to be hydrated, it is appropriateto use from 0.1 to 33 parts by weight of the cocatalyst, preferably from0.5 to 20 parts by weight and very particularly preferably from 1 to 5parts by weight, in particular more than 2 but less than 5 parts byweight, of cocatalyst.

The practical procedure for carrying out this hydration is adequatelyknown to those skilled in the art from U.S. Pat. No. 6,683,136. Thenitrile rubber to be hydrated is usually treated in a solvent such astoluene or monochlorobenzene with hydrogen at a temperature in the rangefrom 100 to 150° C. and a pressure in the range from 50 to 150 bar forfrom 2 to 10 hours.

For the purposes of the present invention, hydration is a reaction of atleast 50%, preferably 70-100%, particularly preferably 80-100%, of thedouble bonds present in the starting nitrile rubber. Residual contentsof double bonds in HNBR of from 0 to 8% are also particularly preferred.

When heterogeneous catalysts are used, these are usually supportedcatalysts based on palladium which are supported, for example, oncarbon, silica, calcium carbonate or barium sulphate.

After the hydration is complete, a hydrated nitrile rubber having aMooney viscosity (ML 1+4 at 100° C.), measured in accordance with ASTMStandard D 1646, in the range 1-50 is obtained. This correspondsapproximately to a weight average molecular weight M_(w) in the range2000-400 000g/mol. The Mooney viscosity (ML 1+4 at 100° C.) ispreferably in the range from 5 to 30. This corresponds approximately toa weight average molecular weight M_(w) in the range of about 20 000-200000. Furthermore, the hydrated nitrile rubbers obtained have apolydispersity PDI=M_(w)/M_(n), where M_(w) is the weight averagemolecular weight and M_(n) is the number average molecular weight, inthe range 1-5 and preferably in the range 1.5-3.

However, the catalyst system cannot only be used successfully for themetathetic degradation of nitrile rubbers but can also be useduniversally for other metathesis reactions. In a process forring-closing metathesis, the catalyst system of the invention is broughtinto contact with the appropriate acyclic starting material, e.g.diethyl diallylmalonate.

The use according to the invention of the catalyst systems comprisingmetathesis catalyst and the fluorine-containing boron compound of thegeneral formula (Z) allows, at comparable reaction times, the amount ofthe actual metathesis catalyst and thus the amount of noble metal to besignificantly reduced compared to analogous metathesis reactions inwhich only the catalyst is used, i.e. without addition of afluorine-containing boron compound of the general formula (Z). Whencomparable noble metal contents are used, the reaction time issubstantially shortened by the addition of the fluorine-containing boroncompound of the general formula (Z). When used for the degradation ofnitrile rubbers, degraded nitrile rubbers having significantly lowermolecular weights M_(w) and M_(n) can be achieved.

EXAMPLES

When the following examples are carried out at room temperature, this is22+/−2° C. In the examples below, the complex catalysts shown in Table 1were used.

TABLE 1 Molecular weight Name of catalyst Structural formula [g/mol]Source Grubbs II Catalyst

848.33 Materia/ Pasadena; USA Hoveyda Catalyst

626.14 Aldrich Grela Catalyst

671.13 Prepared as described in J. Org. Chem. 2004, 69, 6894-6896

The following examples according to the invention were carried out usingthe compounds of the general formula (Z) shown in Table 2.

TABLE 2 Name of additive Formula Source Diethyl ether adduct of boronBF₃*C₄H₁₀O Acros trifluoride Organics Ethylamine adduct of borontrifluoride BF₃*EtNH₂ Aldrich Tetrahydrofuran adduct of boron BF₃*C₄H₈OAldrich trifluoride n-Propanol adduct of boron trifluoride BF₃*C₃H₇OHAldrich Acetic acid adduct of boron trifluoride BF₃*CH₃COOH Aldrich

The examples carried out on the metathetic degradation of nitrile rubberare summarized in terms of the complex catalysts used, the compound ofthe general formula (Z) and the molar ratio of complex catalyst:additiveused in Table 3 below.

TABLE 3 Molar ratio of Experiment Catalyst Additive catalyst:additive1.0 not according to Grubbs II — — the invention 1.1 according to GrubbsII BF₃*Et₂O 1:22 the invention 1.2 according to Grubbs II BF₃*Et₂O 1:5 the invention 1.3 according to Grubbs II BF₃*Et₂O 1:2  the invention 1.4according to Grubbs II BF₃*Et₂O 1:1  the invention 1.5 according toGrubbs II BF₃*EtNH₂ 1:22 the invention 1.6 according to Grubbs IIBF₃*THF 1:22 the invention 1.7 according to Grubbs II BF₃*n-Propanol1:22 the invention 1.8 according to Grubbs II BF₃*CH₃COOH 1:22 theinvention 2.0 not according to Grela — — the invention 2.1 according toGrela BF₃*Et₂O 1:22 the invention

Nitrile Rubber Used:

The degradation reactions described in the following examples werecarried out using the nitrile rubber Perbunan® 3436 F from LanxessDeutschland GmbH.

This nitrile rubber had the following characteristic properties:

Acrylonitrile content: 34.3% by weight Mooney Viscosity (ML 1 + 4 at100° C.): 33 Mooney units Residual moisture content: 1.0% by weightM_(w): 211 kg/mol M_(n): 82 kg/mol PDI (M_(w)/M_(n)): 2.6

Procedure for the Metathesis of the Nitrile Rubber:

The metathetic degradation was in each case carried out using 293.3 g ofchlorobenzene (hereinafter referred to as “MCB”/Aldrich), which wasdistilled and made inert at room temperature by passing argon through itbefore use. To carry out the degradation, 40g of NBR were dissolved overa period of 12 hours while stirring at room temperature. In each case,0.8 g (2 phr) of 1-hexene and then the boron compounds indicated in thetables (dissolved in 10g of MCB which had been made inert) were added tothe NBR-containing solution and the mixture was homogenized by stirringfor 30 minutes.

The Ru catalysts (Grubbs II, Hoveyda and Grela catalyst) were in eachcase dissolved under argon in 10g of MCB which had been made inert, withthe addition of the catalyst solutions to the NBR solutions in MCB beingcarried out immediately after the preparation of the catalyst solutions.

The metathesis reactions were carried out at room temperature using theamounts of starting materials indicated in the following tables.

After the reaction times indicated in the tables, about 3 ml were ineach case taken from the reaction solutions and the reaction was stoppedby immediate addition of about 0.2 ml of ethyl vinyl ether. 0.2 ml wastaken from the stopped solution and diluted with 3 ml of DMAc(N,N-dimethylacetamide (stabilized with LiBr 0.075M; from Aldrich)).

To carry out the GPC analysis, the solutions were in each case filteredby means of a 0.2 μm Teflon syringe filter (Chromafil PTFE 0.2 mm; fromMachery-Nagel). The GPC analysis was subsequently carried out using aninstrument from Waters (Mod. 510). A combination of a precolumn (PLGuard from Polymer Laboratories) with two Resipore columns (300×7.5 mm,pore size: 3 μm) from Polymer Laboratories was used for the analysis.The columns were calibrated using linear polystyrene having molar massesfrom 960 to 6×10⁵g/mol from Polymer Standards Services. An RI detectorfrom Waters (Waters 410 Differential Refractometer) was used asdetector. The analysis was carried out at a flow rate of 1.0 ml/min at80° C. using N,N′-dimethylacetamide as eluent. The evaluation of the GPCcurves was carried out using software from Polymer Laboratories (CirrusMulti Version 3.0).

-   Series 1: Use of the Grubbs II catalyst in combination with various    fluorine-containing boron compounds in the metathetic degradation of    NBR-   Experiment 1.0: Use of the Grubbs II catalyst without additive (not    according to the invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 — — Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 82 2.6 30139 66 2.1 60 101 54 1.9 185  77 45 1.7 425  62 37 1.7

-   Experiment 1.1: Use of the Grubbs II catalyst in combination with    BF₃*Et₂O at a molar ratio of Grubbs II/BF₃*Et₂O=1:22 (according to    the invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 BF₃*Et₂O 74 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 822.6 30 16 7 2.3 60 10 6 1.7 185  11 6 1.8 425  10 6 1.7

-   Experiment 1.2: Use of the Grubbs II catalyst in combination with    BF₃*Et₂O at a molar ratio of Grubbs IUBF₃*Et₂O=1:5 (according to the    invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 BF₃*Et₂O 16.7 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 21182 2.6 30 115 53 2.2 60 72 36 2.0 185  48 26 1.8 425  34 18 1.9

-   Experiment 1.3: Use of the Grubbs II catalyst in combination with    BF₃*Et₂O at a molar ratio of Grubbs II/BF₃*Et₂O=1:2 (according to    the invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 BF₃*Et₂O 7 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 822.6 30 129 63 2.0 60 92 51 1.8 185  42 20 2.1 425  35 18 1.9

-   Experiment 1.4: Use of the Grubbs II catalyst in combination with    BF₃*Et₂O at a molar ratio of Grubbs II/BF₃*Et₂O=1:1 (according to    the invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 BF₃*Et₂O 3.4 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 822.6 30 136 63 2.2 60 99 53 1.9 185  77 37 2.1 425  59 30 2.0

-   Experiment 1.5: Use of the Grubbs H catalyst in combination with    BF₃*EtNH₂ at a molar ratio of Grubbs II/BF₃*EtNH₂=1:22 (according to    the invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 BF₃*EtNH₂ 59 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 822.6 30 110 49 2.2 60 86 41 2.1 185  71 34 2.1 425  — — —

-   Experiment 1.6: Use of the Grubbs II catalyst in combination with    BF₃*THF at a molar ratio of Grubbs II/BF₃*THF=1:22 (according to the    invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 BF₃*THF 73 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 822.6 30 112 54 2.1 60 — — — 185  — — — 425  — — —

-   Experiment 1.7: Use of the Grubbs II catalyst in combination with    BF₃*n-propanol at a molar ratio of Grubbs IUBF₃*n-propanol=1:22    (according to the invention)

Grubbs II catalyst 1-Hexene Based Based NBR on on Additive Amount AmountNBR Amount NBR Amount [g] [mg] [phr] [g] [phr] Type [mg] 40 20 0.05 0.82.0 BF₃*n- 66 propanol Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0211 82 2.6 30 87 44 2.0 60 64 31 2.1 185  32 17 1.9 425  24 14 1.7

-   Experiment 1.8: Use of the Grubbs II catalyst in combination with    BF₃*CH₃COOH at a molar ratio of Grubbs 11/BF₃*CH₃COOH=1:22    (according to the invention)

Grubbs II catalyst 1-Hexene Based Based on on NBR Amount NBR Amount NBRAdditive Amount [g] [mg] [phr] [g] [phr] Type Amount [mg] 40 20 0.05 0.82.0 BF₃*CH₃COOH 98 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 21182 2.6 30  99 50 2.0 60 — — — 185  — — — 425  — — —

In Series 1, it is shown that when using the Grubbs II catalyst, themetathetic degradation of nitrile rubber is accelerated by addition ofcompounds of the BF₃*D type; i.e. after the same reaction times, M_(w),and M_(n) are significantly lower than in the reference experiment(experiment 1.0) which was carried out without additives. In addition,it is shown that the effect according to the invention occurs atdifferent molar ratios of Grubbs II catalyst: BF₃*D.

-   Series 2: Use of the Grela catalyst in combination with BF₃*Et₂O in    the metathetic degradation of NBR-   Experiment 2.0: Use of the Grela catalyst without addition of boron    compounds (not according to the invention)

Grela catalyst 1-Hexene Based Based NBR on on Additive Amount Amount NBRAmount NBR Amount [g] [mg] [phr] [g] [phr] Type [g] 40 15.8 0.04 0.8 2.0— — Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 82 2.6 30 49 341.4 60 48 31 1.6 185  48 29 1.6 425  50 29 1.7

-   Experiment 2.1: Use of the Grela catalyst in combination with    BF₃*Et₂O at a molar ratio of Grela catalyst/BF₃*Et₂O=1:22 (according    to the invention)

Grela catalyst 1-Hexene Based Based NBR on on Additive Amount Amount NBRAmount NBR Amount [g] [mg] [phr] [g] [phr] Type [g] 40 15.8 0.04 0.8 2.0BF₃*Et₂O 0.0074 Time M_(w) M_(n) [min.] [kg/mol] [kg/mol] PDI  0 211 822.6 30 38 20 1.9 60 33 17 2.0 185  33 17 1.9 425  31 16 1.9

In series 2, it is shown that the metathetic degradation of nitrilerubber is accelerated when the Greta catalyst is used in combinationwith BF₃*Et₂O; i.e. after the same reaction times, M_(w), and M_(n) aresignificantly lower than in the reference experiment (experiment 2.0)which is carried out without an additive.

1. A process for reducing the molecular weight of nitrile rubber,comprising bringing into contact and reacting a nitrile with a catalystsystem, characterized in that the catalyst system comprises a metathesiscatalyst which is a complex catalyst based on a metal of transitiongroup 6 or 8 of the Periodic Table and has at least one ligand bound ina carbene-like fashion to the metal and also at least one compound ofthe general formula (Z)BF_(m)X_(n)*D_(v)  (Z) where m is 1, 2 or 3, n is 0, 1 or 2 and at thesame time m+n=3 and v is 1, 2, 3, 4 or 5, X is chlorine, bromine,iodine, an —OR or —NR₂ group, where the radicals R are each,independently of one another, a linear, branched, aliphatic, cyclic,heterocyclic or aromatic radical which has 1-33 carbon atoms and mayoptionally have from 1 to 15 further heteroatoms, and D is a compoundhaving at least one free electron pair, where D contains at least oneheteroatom.
 2. The process according to claim 1, wherein a complexcatalyst based on molybdenum, tungsten, osmium or ruthenium is used. 3.The process according to claim 1, wherein compounds of the generalformula (A),

where M is osmium or ruthenium, X¹ and X² are identical or different andare two ligands, L represents identical or different ligands, theradicals R are identical or different and are each hydrogen, an alkyl,cycloalkyl, alkenyl, alkynyl, aryl, carboxylate, alkoxy, alkenyloxy,alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio,alkylsulphonyl, or alkylsulphinyl, where these radicals can alloptionally be substituted by one or more alkyl, halogen, alkoxy, aryl-or heteroaryl radicals or alternatively the two radicals R are bridgedwith inclusion of the common C atom to which they are bound to form acyclic group which can be aliphatic or aromatic in nature, mayoptionally be substituted and can contain one or more heteroatoms, areused as catalyst.
 4. The process according to claim 3, wherein X¹ and X²are identical or different and anionic ligands, L represents unchargedelectron donors, the radicals R are identical or different and are eachhydrogen, C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl, C₂-C₂₀-alkenyl,C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, carboxylate, C₁-C₂₀-alkoxy,C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy,C₂-C₂₀-alkoxycarbonyl, C₁-C₃₀-alkylamino, C₁-C₃₀ alkylthio,C₆-C₂₄-arylthio, C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphinyl, wherethese radicals can all optionally be substituted by one or more alkyl,halogen, alkoxy, aryl- or heteroaryl radicals or alternatively the tworadicals R are bridged with inclusion of the common C atom to which theyare bound to form a cyclic group which can be aliphatic or aromatic innature, may optionally be substituted and can contain one or moreheteroatoms.
 5. The process according to claim 3, wherein X¹ and X² areidentical or different and are each hydrogen, halogen, pseudohalogen,straight-chain or branched C₁-C₃₀-alkyl, C₆-C₂₄-aryl, C₁-C₂₀-alkoxy,C₆-C₂₄-aryloxy, C₃-C₂₀-alkyldiketonate, C₆-C₂₄-aryldiketonate,C₁-C₂₀-carboxylate, C₁-C₂₀-alkylsulphonate, C₆-C₂₄-arylsulphonate,C₁-C₂₀-alkylthiol, C₆-C₂₄-arylthiol, C₁-C₂₀-alkylsulphonyl orC₁-C₂₀-alkylsulphinyl.
 6. The process according to claim 3, wherein X¹and X² are identical or different and are each fluorine, chlorine,bromine or iodine, benzoate, C₁-C₅-carboxylate, C₁-C₅-alkyl, phenoxy,C₁-C₅-alkoxy, C₁-C₅-alkylthiol, C₆-C₂₄-arylthiol, C₆-C₂₄-aryl orC₁-C₅-alkylsulphonate.
 7. The process according to claim 3, wherein X¹and X² are identical and are each chlorine, CF₃COO, CH₃COO, CFH,COO,(CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO (phenoxy), MeO (methoxy),EtO (ethoxy), tosylate (p-CH₃—C₆H₄—SO₃), mesylate(2,4,6-trimethylphenyl) or CF₃SO₃ (trifluoromethanesulphonate).
 8. Theprocess according to claim 3, wherein the two ligands L are each,independently of one another, a phosphine, sulphonated phosphine,phosphate, phosphinite, phosphonite, arsine, stibine, ether, amine,amide, sulphoxide, carboxyl, nitrosyl, pyridine, thioether orimidazolidine (“Im”) ligand.
 9. The process according to claim 8,wherein the imidazolidine radical (Im) has a structure of the generalformulae (IIa) or (IIb),

where R⁸, R⁹, R¹⁰, R¹¹ are identical or different and are each hydrogen,straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate,C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₀-aryloxy,C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio, C₆-C₂₀-arylthio,C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphonate, C₆-C₂₀-arylsulphonate orC₁-C₂₀ alkylsulphinyl, where all the abovementioned radicals mayoptionally be substituted.
 10. The process according to claim 1, whereincatalysts of the general formula (A1),

where X¹ and X² are identical or different and are two ligands, Lrepresents identical or different ligands, n is 0, 1 or 2, m is 0, 1, 2,3 or 4 and the radicals R′ are identical or different and are each analkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy,alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio,alkylsulphonyl or alkylsulphinyl radical, which may all be substitutedby one or more alkyl, halogen, alkoxy, aryl or heteroaryl radicals, areused.
 11. The process according to claim 1, wherein the catalyst has thestructure (IV), (V) or (VI), where Cy is in each case cyclohexyl, Mes is2,4,6-trimethylphenyl and Ph is phenyl.


12. The process according to claim 1, wherein catalysts of the generalformula (B),

where M is ruthenium or osmium, Y is oxygen (O), sulphur (S), an N—R¹radical or a P—R¹ radical, X¹ and X² are identical or different ligands,R¹ is an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy, alkenyloxy,alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio,alkylsulphonyl or alkylsulphinyl radical, which may all optionally besubstituted by one or more alkyl, halogen, alkoxy, aryl or heteroarylradicals, R², R³, R⁴ and R⁵ are identical or different and are eachhydrogen or an organic or inorganic radical, R⁶ is hydrogen or an alkyl,alkenyl, alkynyl or aryl radical and L is a ligand which has the samemeanings as the ligand L in the formula (A), are used.
 13. The processaccording to claim 12, wherein L is a P(R⁷)₃ radical, where the radicalsR⁷ are each, independently of one another, C₁-C₆-alkyl, C₃-C₈-cycloalkylor aryl or else L is a substituted or unsubstituted imidazolidineradical (“IM”)
 14. The process according to claim 13, wherein theimidazolidine radical (“Im”) has one of the structures (IIIa) to (IIIf)below, where Ph is in each case phenyl, Bu is butyl and Mes is a2,4,6-trimethylphenyl radical or alternatively in each case a2,6-diisopropylphenyl radical.


15. The process according to claim 12, wherein X¹ and X² in the generalformula (B) can have the meanings of X¹ and X² a. are identical ordifferent and are each hydrogen, halogen, pseudohalogen, straight-chainor branched C₁-C₃₀-alkyl, C₆-C₂₄-aryl, C₁-C₂₀-alkoxy, C₆-C₂₄-aryloxy,C₃-C₂₀-alkyldiketonate, C₆-C₂₄-aryldiketonate, C₁-C₂₀-carboxylate,C₁-C₂₀-alkylsulphonate, C₆-C₂₄-arylsulphonate, C₁-C₂₀-alkylthiol,C₆-C₂₄-arylthiol, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl; or b.are identical or different and are each fluorine, chlorine, bromine oriodine, benzoate, C₁-C₅-carboxylate, C₁-C₅-alkyl, phenoxy, C₁-C₅-alkoxy,C₁-C₅-alkylthiol, C₆-C₂₄-arylthiol, C₆-C₂₄-aryl orC₁-C₅-alkylsulphonate; or c. are identical and are each chlorine,CF₃COO, CH₃COO, CFH₂COO, (CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO(phenoxy), MeO (methoxy), EtO (ethoxy), tosylate (p-CH₃—C₆H₄—SO₃),mesylate (2,4,6-trimethylphenyl) or CF₃SO₃ (trifluoromethanesulphonate).16. The process according to claim 1, wherein catalysts of the generalformula (B1),

where is ruthenium or osmium, X¹ and X² are identical or differentligands, R¹ is an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkoxy,alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylamino, alkylthio,arylthio, alkylsulphonyl or alkylsulphinyl radical, which may alloptionally be substituted by one or more alkyl, halogen, alkoxy, aryl orheteroaryl radicals, R², R³, R⁴ and R⁵ are identical or different andare each hydrogen or an organic or inorganic radical, L representsidentical or different ligands.
 17. The process according to claim 16,wherein catalysts of the general formula (B1) in which M is ruthenium,X¹ and X² are both halogen, in particular chlorine. R¹ is astraight-chain or branched C₁-C₁₂ alkyl radical, R², R³, R⁴, R⁵ areidentical or different and are each hydrogen or an organic or inorganicradical, and L represents identical or different ligands, are used. 18.The process according to claim 16, wherein catalysts of the generalformula (B1) in which M is ruthenium, X¹ and X² are both chlorine, R¹ isan isopropyl radical, R², R³, R⁴, R⁵ are all hydrogen and L is asubstituted or unsubstituted imidazolidine radical of the formula (IIa)or (IIb),

where R⁸, R⁹, R¹⁰, R¹¹ are identical or different and are each hydrogen,straight-chain or branched C₁-C₃₀-alkyl, C₃-C₂₀-cycloalkyl,C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate,C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy,C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio, C₆-C₂₄-arylthio,C₁-C₂₀-alkylsulphonyl, C₁-C₂₀-alkylsulphonate, C₆-C₂₄-arylsulphonate orC₁-C₂₀-alkylsulphinyl, are used.
 19. The process according to claim 1,wherein a catalyst having one of the structures (VH), (VIII), (IX), (X),(XI), (XII), (XIII), (XIV) and (XV), where Mes is in each case2,4,6-trimethylphenyl, is used as catalyst.


20. The process according to claim 12, wherein a catalyst of the generalformula (B2),

where M, L, X¹, X², R¹ and R⁶ have the meanings given for the generalformula (B) in claim 12, the radicals R¹² are identical or different andhave the meanings given for the radicals R², R³, R⁴ and R⁵ in thegeneral formula (B) in claim 12, with the exception of hydrogen, and nis 0, 1, 2 or 3, is used.
 21. The process according to claim 20, whereina catalyst having one of the following structures (XVI) and (XVII),where Mes is in each case 2,4,6-trimethylphenyl, is used.


22. The process according to claim 12, wherein a catalyst of the generalformula (B3),

where D¹, D², D³ and D⁴ in each case have a structure of the generalformula (XVIII) shown below which is bound via the methylene group tothe silicon of the formula (B3),

where M, L, X¹, X², R¹, R², R³, R⁵ and R⁶ have the meanings given forthe general formula (B) in Claim 12, is used.
 23. The process accordingto claim 1, wherein a catalyst of the general formula (B4),

where the symbol  represents a support, is used.
 24. The processaccording to claim 1, wherein a catalyst of the general formula (C),

where M is ruthenium or osmium, X¹ and X² are identical or different andare anionic ligands, the radicals R′ are identical or different and areorganic radicals, Im is a substituted or unsubstituted imidazolidineradical and An is an anion, is used.
 25. The process according to claim1, wherein a catalyst of the general formula (D),

where M is ruthenium or osmium, R¹³ and R¹⁴ are each, independently ofone another, hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl,C₆-C₂₄-aryl, C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyloxy,C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy, C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀alkylthio, C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl, X³ is ananionic ligand, L² is an uncharged π-bonded ligand, either monocyclic orpolycyclic, L³ is a ligand from the group consisting of phosphines,sulphonated phosphines, fluorinated phosphines, functionalizedphosphines having up to three aminoalkyl, ammonioalkyl, alkoxyalkyl,alkoxycarbonylalkyl, hydrocarbonylalkyl, hydroxyalkyl or ketoalkylgroups, phosphites, phosphinites, phosphonites, phosphinamines, arsines,stibines, ethers, amines, amides, imines, sulphoxides, thioethers andpyridines, Y⁻ is a noncoordinating anion and n is 0, 1, 2, 3, 4 or 5, isused.
 26. The process according to claim 1, wherein a catalyst of thegeneral formula (E),

where M² is molybdenum or tungsten, R¹⁵ and R¹⁶ are identical ordifferent and are each hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl,C₂-C₂₀-alkynyl, C₆-C₂₄-aryl, C₁-C₂₀-carboxylate, C₁-C₂₀-alkoxy,C₂-C₂₀-alkenyloxy, C₂-C₂₀-alkynyloxy, C₆-C₂₄-aryloxy,C₂-C₂₀-alkoxycarbonyl, C₁-C₂₀-alkylthio, C₁-C₂₀-alkylsulphonyl orC₁-C₂₀-alkylsulphinyl, R¹⁷ and R¹⁸ are identical or different and areeach a substituted or halogen-substituted C₁-C₂₀ alkyl, C₆-C₂₄-aryl,C₆-C₃₀-aralkyl radical or a silicone-containing analogue thereof, isused.
 27. The process according to claim 1, wherein a catalyst of thegeneral formula (F),

where M is ruthenium or osmium, X¹ and X² are identical or different andare anionic ligands L represents identical or different ligands whichcan have all the meanings of L in the general formulae (A) and (B) andR¹⁹ and R²⁰ are identical or different and are each hydrogen orsubstituted or unsubstituted alkyl, is used.
 28. The process accordingto claim 1, wherein a catalyst of the general formula (G), (H) or (K),

where M is osmium or ruthenium, X¹ and X² are identical or different andare two ligands, L is a ligand, Z¹ and Z² are identical or different andare uncharged electron donors, R²¹ and R²² are each, independently ofone another, hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl,carboxylate, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl,alkylamino, alkylthio, alkylsulphonyl or alkylsulphinyl, each of whichmay be substituted by one or more radicals selected from among alkyl,halogen, alkoxy, aryl and heteroaryl, is used.
 29. The process accordingto claim 28 wherein X¹ and X² are identical or different anionic ligandsand L is an uncharged electron donor.
 30. The process according to claim1, characterized in that the catalyst system comprises at least onecompound of the general formula (Z) and a catalyst (N) which has thegeneral structural element (N1),

where the carbon atom denoted by “*” is bound via one or more doublebonds to the basic catalyst framework and R²⁵-R³² are identical ordifferent and are each hydrogen, halogen, hydroxyl, aldehyde, keto,thiol, CF₃, nitro, nitroso, cyano, thiocyano, isocyanato, carbodiimide,carbamate, thiocarbamate, dithiocarbamate, amino, amido, imino, silyl,sulphonate (—SO₃ ⁻), —OSO₃ ⁻, —PO₃ ⁻ or OPO₃ ⁻ or alkyl, cycloalkyl,alkenyl, alkynyl, aryl, carboxylate, alkoxy, alkenyloxy, alkynyloxy,aryloxy, alkoxycarbonyl, alkylamino, alkylthio, arylthio,alkylsulphonyl, alkylsulphinyl, dialkylamino, alkylsilyl or alkoxysilyl,where these radicals can all optionally be substituted by one or morealkyl, halogen, alkoxy, aryl or heteroaryl radicals, or alternativelytwo directly adjacent radicals from the group consisting of R²⁵-R³² canbe bridged with inclusion of the ring carbons to which they are bound toform a cyclic group, optionally an aromatic system, or alternatively R⁸may be bridged to another ligand of the ruthenium- or osmium-carbenecomplex catalyst, m is 0 or 1 and A is oxygen, sulphur, C(R³³R³⁴),N—R³⁵, —C(R³⁶)═C(R³⁷)—, —C(R³⁶)(R³⁸)—C(R³⁷)(R³⁹)—, where R³³-R³⁹ areidentical or different and can each have the same meanings as theradicals R²⁵-R³².
 31. The process according to claim 1, wherein acompound of the general formula (Z) in which D can have the followingmeanings of the general formulae (2) to (16)OR₂  (2)ROH  (3)R—COOH  (4)SR₂  (5)O═SR₂  (6)O₂SR₂  (7)NHR₂, NH₂R, NR₃  (8a, 8b, 8c)YR₃, R₂Y—YR₂  (9a, 9b)O═YR₃  (10)O═Y(OR)₂  (11)O═Y(OR)₃  (12)O═CR₂  (13)S═YR₃  (14)H₂SO₄  (15)RSO₃H  (16) where Y is phosphorus, arsenic or antimony and the radicalsR are identical or different and are each hydrogen or a linear,branched, aliphatic, cyclic, heterocyclic or aromatic radical which has1-33 carbon atoms and may be bridged and can optionally have from 1 to15 further heteroatoms, is used.
 32. The process according to claim 1,wherein, in the compound of the general formula (Z), D is selected fromthe group consisting of water, diethyl ether, ethylamine, THF,n-propanol, formic acid, acetic acid, trifluoroacetic acid,trichloroacetic acid, sulphuric acid, phosphoric acid,trifluoromethanesulphonic acid and toluenesulphonic acid with v=1, 2 or3.
 33. The process according to claim 1, wherein BF_(m)X_(n) in thegeneral formula (Z) is selected from the group consisting of BF₃, BF₂Cl,BFCl₂ BF₂Br, BFBr₂, BF₂(OC₂H₅), BF(OC₂H₅)₂, BF₂(CH₃) and BF(CH₃)₂. 34.The process according to claim 1, wherein the complex catalyst and thecompound of the general formula (Z) are used in a molar ratio of[complex catalyst:compound of the general formula (Z) of 1:(0.1-1000).35. The process according to claim 1, wherein the complex catalyst andthe compound of the general formula (Z) are used in a molar ratio of[complex catalyst:compound of the general formula (Z) of 1:(0.5-100).36. The process according to claim 1, wherein the complex catalyst andthe compound of the general formula (Z) are used in a molar ratio of[complex catalyst:compound of the general formula (Z) of 1:(1-50). 37.The process according to claim 1, wherein a copolymer or terpolymerwhich contains repeating units of at least one conjugated diene, and atleast one α,β-unsaturated nitrile is used as nitrile rubber.
 38. Theprocess according to claim 1, wherein a copolymer or terpolymer whichcontains repeating units of at least one conjugated diene, at least oneα,β-unsaturated nitrile and one or more further copolymerizable monomersis used as nitrile rubber.
 39. The process according to claim 1, whereinthe compound of the general formula (Z) is added in a solvent ordispersion medium or alternatively without solvent or dispersion mediumto the complex catalyst or a solution of the complex catalyst.
 40. Theprocess according to claim 1, wherein the amount of the complex catalystpresent in the catalyst system corresponds to from 1 to 1000 ppm ofnoble metal, based on the nitrile rubber used.
 41. The process accordingto claim 1, wherein the amount of the complex catalyst present in thecatalyst system corresponds to from 2 to 500 ppm of noble metal based onthe nitrile rubber used.
 42. The process according to claim 1, whereinthe amount of the complex catalyst present in the catalyst systemcorresponds to from 5 to 250 ppm of noble metal based on the nitrilerubber used.
 44. The process according to claim 1, wherein the reactionis carried out in the presence of a co-olefin.
 45. The process accordingto claim 3, wherein X¹ and X² of the general formula (A) are anionicligands.
 46. The process according to claim 3, wherein the radicals Rcompounds of the general formula (A) are identical or different and areeach hydrogen, an alkyl, selected from the group containingC₁-C₃₀-alkyl, cycloalkyl, selected from the group containingC₃-C₂₀-cycloalkyl, alkenyl, selected from the group containingC₂-C₂₀-alkenyl, alkynyl, selected from the group containingC₂-C₂₀-alkynyl, aryl, selected from the group containing C₆-C₂₄-aryl,carboxylate, selected from the group containing C₁-C₂₀-carboxylate,alkoxy, selected from the group containing C₁-C₂₀-alkoxy, alkenyloxy,selected from the group containing C₂-C₂₀-alkenyloxy, alkynyloxy,selected from the group containing C₂-C₂₀-alkynyloxy, aryloxy, selectedfrom the group containing C₆-C₂₄-aryloxy, alkoxycarbonyl, selected fromthe group containing C₂-C₂₀-alkoxycarbonyl, alkylamino, selected fromthe group containing C₁-C₃₀-alkylamino, alkylthio, selected from thegroup containing C₁-C₃₀-alkylthio, arylthio, selected from the groupcontaining C₆-C₂₄-arylthio, alkylsulphonyl, selected from the groupcontaining C₁-C₂₀-alkylsulphonyl, or alkylsulphinyl, selected from thegroup containing C₁-C₂₀-alkylsulphinyl, where these radicals can alloptionally be substituted by one or more alkyl, halogen, selected fromthe group containing fluorine or chlorine, alkoxy, aryl- or heteroarylradicals or alternatively the two radicals R are bridged with inclusionof the common C atom to which they are bound to form a cyclic groupwhich can be aliphatic or aromatic in nature, may optionally besubstituted and can contain one or more heteroatoms.
 47. The processaccording to claim 27, wherein X¹ and X² of the general formula (F), areidentical or different and are anionic ligands which can have all themeanings a. are identical or different and are each hydrogen, halogen,pseudohalogen, straight-chain or branched C₁-C₃₀-alkyl, C₆-C₂₄-aryl,C₁-C₂₀-alkoxy, C₆-C₂₄-aryloxy, C₃-C₂₀-alkyldiketonate,C₆-C₂₄-aryldiketonate, C₁-C₂₀-carboxylate, C₁-C₂₀-alkylsulphonate,C₅-C₂₄-arylsulphonate, C₁-C₂₀-alkylthiol, C₆-C₂₄-arylthiol,C₁-C₂₀-alkylsulphonyl or C₁-C₂₀-alkylsulphinyl; or b. are identical ordifferent and are each fluorine, chlorine, bromine or iodine, benzoate,C₁-C₅-carboxylate, C₁-C₅-alkyl, phenoxy, C₁-0₅-alkoxy, C₆-C₂₄-arylthiol,C₆-C₂₄-aryl or C₁-C₅-alkylsulphonate; or c. are identical and are eachchlorine, CF₃COO, CH₃COO, CFH₃COO, (CH₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO,PhO (phenoxy), MeO (methoxy), EtO (ethoxy), tosylate (p-CH₃—C₆H₄—SO₃),mesylate (2,4,6-trimethylphenyl) or CF₃SO₃ (trifluoromethanesulphonate).48. The process described in claim 1 wherein D of the formula (Z) isselected from the group consisting of oxygen, sulphur, nitrogen,phosphorus, arsenic and antimony.
 49. The process according to claim 31wherein Y heteroatoms are selected from the group containing oxygen ornitrogen.